Method for culturing Chinese hamster ovary cells

- GlaxoSmithKline LLC

A biochemically defined culture medium for culturing engineered Chinese hamster ovary (CHO) cell lines, which is essentially free from protein, lipid and carbohydrate isolated from an animal source, having water, an osmolality regulator, a buffer, an energy source, amino acids including L-glutamine, an inorganic or recombinant iron source, and a synthetic or recombinant growth factor, and optionally non-ferrous metal ions vitamins and cofactors. Also cells adapted to grow in such a culture medium.

Skip to: Description  ·  Claims  ·  References Cited  · Patent History  ·  Patent History
Description

This is a continuation of application Ser. No. 07,991,717 filed Dec. 18, 1992, now U.S. Pat. No. 5,316,938 which is a continuation of Ser. No. 07/777,729, filed Oct. 16, 1991, now abandoned. Notice: more than one reissue application has been filed for reissue of U.S. Pat. No. 5,633,162. The reissue applications are application Ser. No. 11/640,428 (the present application), filed on 15 Dec. 2006; and application Ser. No. 10/995,010, filed on 22 Nov. 2004, now RE 39.792.

The present reissue application is a continuation of application Ser. No. 10/995,010, now Reissue No. RE 39,792, filed 22 Nov. 2004, which is a reissue application of U.S. Pat. No. 5,633,162, U.S. Pat. No. 5,633,162, filed as application Ser. No. 08/205,379 on 4 Mar. 1994, is a continuation of U.S. Ser. No. 07/991,717 filed 18 Dec. 1992, now U.S. Pat. No. 5,316,938, which is a continuation of U.S. Ser. No. 07/777,729 filed 16 Oct. 1991, now abandoned.

The present invention relates to a biochemically defined culture medium for culturing Chinese hamster ovary (CHO) cell lines and cells adapted to grow in the culture medium.

Chinese hamster ovary cells (CHO) were first cultured by Puck (J. Exp. Med. 108, 945, 1958) from a biopsy of an ovary from a female Chinese hamster. From these original cells various workers have cloned a number of sub-lines with various deficiencies, one of which, CHO-K1, is proline-requiring and is diploid for the dihydrofolate reduotase (dhfr) gene. From this cell line a dhfr− CHO cell line (CHO DUK B11) was developed (PNAS 77, 1980, 4216-4220) which is characterised by the loss of dhfr function as a consequence of a mutation in one dhfr gene and the subsequent loss of the other gene. These cells are functionally dhfr−. Other OHO DUK sub-lines have been derived which are also phenotypically dhfr−. CHO cells which are dhfr− cannot grow without nucleotide precursors such as thymidine, hypoxanthine, or the equivalent nucleosides.

Various proteins have been expressed in such CHO cells including E. coli XGPRT gene (J. Mol. App. Gen. 1981, 1, 165-175), human tissue-type plasminogen activator (Mol. & Cell Biol. 5, 170-1759, 1985), human immune (γ) interferon (PNAS 80 pp 4654-4658), and human beta interferon (Molecular and Cellular Biology 4, 166-172, 1984). A dhfr− CHO cell line is transfected with a product gene and a dhfr gene which enables selection of CHO cell transformants of the dhfr+ phenotype. Selection is carried out by culturing the colonies in media devoid of thymidine and hypoxanthine, the absence of which prevents untransformed cells from growing. The transformants usually express low levels of the product gene by virtue of co-integration of both transfected genes. The expression levels for the product gene may be increased by amplification using methotrexate. This drug is a direct inhibitor of the dhfr enzyme and allows isolation of resistant colonies which have amplified their dhfr gene copy number sufficiently to survive under these conditions. Since the dhfr and product genes are usually closely linked in the original transformants, there is normally concomitant amplification resulting in increased expression of the desired product gene.

A different system of selection and amplification is provided by the glutamine synthetase selectable marker (or GS system) which is described in WO87/04462. CHO cells which have been successfully transfected with the gene encoding the GS enzyme and the desired antibody gene can be selected by culturing colonies in media devoid of glutamine and amplifying by the addition of methionine sulphoximine (Msx) as described in PCT published application number WO87/04462.

Engineered CHO cells (those in which a CHO cell line is transfected with a product gene and a selectable marker gene) are routinely grown in culture media containing serum, (References: J. Mol. App. Gen. 1981, 1, 165-175; Mol. & Cell Biol. 1985, 5, 1750-1759, 1985 ; PNAS 1983, 80, pp 4654-4658; Molecular and Cellular Biology 1984, 4, 166-172, 1984 ). Fetal bovine serum (FBS) is probably the most extensively utilised serum for mammalian cell culture, although other mammalian sera are used. However, the use of serum poses a number of problems. Serum is an expensive commodity which is not readily available in amounts required for commercial production. It is also a biochemically undefined material. Serum is known to contain many major components including albumin and transferrin and also minor components many of which have not been fully identified nor their action determined, thus serum will differ from batch to batch possibly requiring testing to determine levels of the various components and their effect on the cells. Frequently, serum is contaminated with microorganisms such as viruses and mycoplasma many of which may be harmless but will represent an additional unknown factor. This problem has become more acute in recent years with the emergence of Bovine Spongiform Encephalopathy (BSE). Despite improvements in screening, regulatory authorities are likely to require the sourcing of bovine products from those areas which are free from (BSE) infections. Furthermore, the presence of animal proteins in culture media can require lengthy purification procedures, in particular the presence of bovine antibodies in bovine serum albumin (BSA) makes purification of the desired antibodies expressed by the recombinant CHO cell line, extremely difficult. Removal of bovine antibody from the medium prior to use is possible but this and the additional product testing required, adds greatly to the everall overall cost of production of the product. Consequently, there has been much research into finding a culture medium devoid of animal components which will support cellular growth, especially of CHO cells. Unfortunately, the problems associated with the provision of such a medium are themselves numerous. CHO cells do not readily grow in serum-free conditions. In addition, the removal of serum may also remove those components that provide cell protection and detoxifying activity.

A culture medium which is serum-free but not free from animal components is described by Mendiaz et al (In Vitro Cellular & Development Biology Vol.22, No.2, 1986) for use in the culture of CHO K1 cells. The medium is a modification of the medium developed by Ham (Microbiology 53 1965 288-293) which is known as “Ham's F12”. Other examples of media have been based on Ham's F12 medium for example as disclosed in EPA390327 and EP325190. These media contain transferrin as the serum substitute, but transferrin is derived from an animal source, so the resulting media do not overcome the contamination problems associated with the use of serum.

A further problem which arises with the use of serum-free media is that of supporting recombinant CHO cells to enable growth and expression of product. Media based on Ham's F12 which are not supplemented with serum are generally not rich enough to support full growth or expression.

Engineered CHO cells are also difficult to grow in suspension. It is highly desirable to achieve growth in suspension when using the cells to express a product such as an antibody. For production of a biological protein on a commercial scale it is preferable to be able to support growth in fermenters fermentors which range from 1 liter glass vessels to multi-thousand liter stainless steel tanks. A suitable medium must be able to support the cells against sheer forces from blade impellers or turbines and from effects of sparging (ie: supplying air, oxygen and CO2 in bubble form directly to the medium).

The present invention therefore provides a biochemically defined culture medium for culturing engineered CHO cells which is essentially free from protein, lipid and carbohydrate isolated from an animal source, comprising water, an osmolality regulator, a buffer, an energy source, amino acids including L-glutamine, an inorganic or recombinant iron source and a recombinant or synthetic growth factor and optionally non-ferrous metal ions, vitamins and cofactors.

The components of the medium are mostly inorganic, synthetic or recombinant and as such are not obtained directly from any animal source. Some components may be obtained from a plant or bacterial source. Recombinant components are prepared under highly pure conditions to minimise the risk of contamination from the parent tissue passing to the cells used to produce the components. Further purification steps may be employed to remove cell proteins. Thus, a medium which is essentially free from all protein, lipid and carbohydrate isolated from an animal source, can be achieved. The preferred culture medium of the invention contains no protein, lipid and carbohydrate isolated from an animal source.

It is advantageous to maintain osmolality in the range 200-30 milli-Osmols (mOsm) preferably in the range 290-350 mOsm. Osmolality regulators are generally salts. Those which may be used in the medium include NaCl, KCl, KNO3.

Buffers of use in the medium to maintain the pH in the range 6.5-7.5 most preferably around pH 7.0. Buffers of use in the medium include carbonates such as NaHCO3; also chlorides, sulphates and phosphates such as CaCl22H2O, MgSO47H2O, NaH2PO42H2O, or sodium pyruvate, such buffers are generally present in an amount 50-500 mg/liter. Other buffers, such as N-[2-hydroxyethyl]piperazine-N′-[2-ethanesul-phonic acid] otherwise known as HEPES and 3-[N-Morpholino]-propanesul-fonic acid otherwise known as MOPS are generally present in an amount 1000-10,000 mg/liter.

The energy source of use in the medium is generally present in an amount 1000-10,000 mg/liter and is preferably a monosaccharide such as manose, fructose, galactose or maltose most preferably glucose, particularly D-glucose.

The non-ferous non-ferrous metal ions optionally of use in the medium include magnesium, copper and zinc; also sodium, potassium and selenium. The ions are generally added to the medium in the form of salts such as chlorides and sulphates sulfates. The amounts are typically similar to those provided in the ISCOVES medium set out in Table 1 but clearly may be varied.

Vitamins and enzyme co-factor vitamins (co-factors) optionally of use in the medium include Vitamin B6 (pyridoxine). Vitamin B12 (cyanocobalamin) and Vitamin K (biotin) present in an amount 0.01-0.5 mg/liter; Vitamin C (ascorbic acid) present in an amount 10-30 mg/liter. Vitamin B2 (riboflavin) present in an amount 0.1-1.0 mg/liter and Vitamin B1 (thiamine), nicotin amide. Vitamin B5 (D calcium pentothenate), folic acid, i-inositol generally present in an amount 0.2-8.0 mg/liter.

It is preferable to include in the basal medium a lipid factor such as choline chloride, lipoic acid, oleic acid, phosphatidylcholine or methyl lineoleate, generally in an amount 0.05-10 mg/liter. Compounds involved in lipid production for example alcoholamines such as ethanolamine may also be added.

It is preferable to include additional amino acids in the medium selected from:

Amino Acid Preferred mg/liter L-Alanine 20-50 L-Arginine (HCl)  50-100 L-Asparagine (H2O) 20-50 L-Aspartic Acid 20-50 L-Cystine (disodium salt)  50-100 L-Glutamic acid  50-100 L-Glutamine 400-600 Glycine 20-50 L-Histidine (HCl•H2O) 30-60 L-Isoleucine  50-150 L-Leucine  50-150 L-Lysine (HCl) 100-200 L-Methionine 20-50 L-Phenylalanine 40-80 L-Proline 30-60 L-Serine 30-60 L-Threonine  50-120 L-Tryptophan 10-20 L-Tyrosine (disodium salt)  50-120 L-Valine  80-120

The bracketed forms are preferred.

The amino acids are preferably of synthetic origin. The amounts which are usually included vary for each amino acid but are generally in the range 10-150 mg/ml. However, L-glutamine is generally present at much higher concentration preferably in the range 400-600 mg/ml mg/liter.

It may be advantageous to include in the medium a pH indicator for example Phenol red sodium salt for example at 5-50 mg/liter.

Medium A as set out in Table 1, is an example of a medium which provides the preferred quantities of water, osmolality regulator, buffer, energy source, amino acids, non-ferrous metal ions, vitamins and co-factors as a basis for a culture medium according to the invention. This medium does not contain any hypoxanthine or thymidine and is commercially available from GIBCO Ltd., Unit 4, Cowley Mill Td. Est., Uxbridge UB8 2YG. It is similar to a published culture medium (Iscoves and Melcher (1978) J. Exp. Med. 1, 47,923) but does not contain any bovine serum albumin, pure human transferrin or soyabean lecithin.

TABLE 1 Medium A (modification of Iscoves' DMEM lacking albumin, transferrin and lecithin) Ingredient mg/liter L-Alanine 25.00 L-Arginine HCl 84.00 L-Asparagine H2O 28.40 L-Aspartic Acid 30.00 L-Cystine 70.00 L-Glutamic acid 75.00 L-Glutamine 584.00 Glycine 30.00 L-Histidine HCl•H2O 42.00 L-Isoleucine 105.00 L-Leucine 105.00 L-Lysine HCl 146.00 L-Methionine 30.00 L-Phenylalanine 66.00 L-Proline 40.00 L-Serine 42.00 L-Threonine 95.00 L-Tryptophan 16.00 L-Tyrosine disodium salt 104.00 L-Valine 94.00 Biotin 0.013 D.Calcium Pantothenate 4.00 Choline chloride 4.00 Folic acid 4.00 i-Inositol 7.20 Nicotinamide 4.00 Pyridoxal HCl 4.00 Riboflavin 0.40 Thiamin HCl 4.00 Vitamin B 12 0.013 CaCl22H2O 219.00 KCl 330.00 KNO3 0.076 MgSO47H2O 200.00 NaCl 4505.00 NaHCO3 3024.00 NaH2PO42H2O 141.30 D-Glucose 4500.00 HEPES 5958.00 Phenol red sodium salt 15.00 Sodium pyruvate 110.00 Sodium selenite 0.017

DMEM modification of Iscoves N and Melcher (1978), J. Exp. Med. 1, 47, 923.

It is preferable to add to the medium, selenium (optionally in the form of sodium selenite) generally in an amount 0.01-0.2 mg/liter or L-Ascorbic acid generally in an amount 20-50 mg/liter to help minimise the potential toxic effects of ferrous or ferric ions, and oxygen. Further use of chelating agents such as citrate or Ethylenediaminetetraacetic acid (EDTA) or a free radical scavenger such as α-Tocepherol (vitamin E) are advantageous in reducing free radical damage.

Antibiotics such as polymyxin, neomycin, penicillin or streptomycin may be added to-the medium to prevent bacterial contamination. These are usually included in an amount 10,000-100,000 Iu/liter.

Growth factors which may be added to the basal medium are synthetic or recombinant and include insulin. Other factors such as platelet-derived growth factor (PDGF), thyroxtne thyroxine T3, thrombin, interleukins such as IL2 and IL6, progesterone, hydrocortisone and vitamin E may be included. Folic acid, vitamin B6 and vitamin B12 which are involved in the folate pathway may be added to enhance the growth of cells.

The peptide hormone insulin (which in the present context includes analogues thereof such as Nucellin® (recombinant insulin, Eli Lilly) is advantageously obtained by recombinant DNA techniques but is not isolated from an animal source. It is preferably added to the medium in an amount 5 μg-5 mg/liter. Nucellin is the preferred form of insulin for use in the invention.

The non-animal derived iron source to supplement the medium, is preferably inorganic and present in an amount 0.25-5 mg/liter. Examples include ferric and ferrous salts such as ferric citrate or ferrous sulphate. The chelated salts such as ferric citrate and ferric ammonium citrate are preferred. However, any iron source may be used which is not isolated from an animal source, for example, chemical iron chelators or recombinant protein iron carriers.

The concentration of ferric or ferrous ions should be carefully controlled as these may help generate superoxides and free radicals in the medium, which may damage not only the cells themselves, but medium components and the desired end product.

It is also preferable to add to the medium, a compound such as putrescine, advantageously as a salt such as HCl, which is known to play a role in maintaining the structure of the endoplasmic reticulum and to be required by certain CHO cell lines to support growth. Putrescine or a salt thereof is preferably added in an amount 0.01-1.0 mg/liter.

Serum-free media disclosed to date contain hypoxanthine or thymidine. This could bypass the selection pressure placed on the dhfr selection and amplification system as previously disclosed. The result may be loss of genetic material specifying the product and the dhfr genes. Therefore, In another aspect of the invention there is provided a culture medium for the growth of engineered dhfr− CHO cells in accordance with the invention, essentially free from hypoxanthine and/or thymidine.

The culture medium of the present invention supports CHO cell growth and when supplemented with an appropriate agent such as methotrexate for the dhfr system usually in an amount 0.1-5.0 μM, (or MSX for the GS system), allow full selection pressure to be exerted on the cells. It will be understood that hypoxanthine and thymidine at concentrations which are insufficient to bypass selection of the dhfr system may be present in the medium, but the presence of these two nucleotide precursors is not preferred for use with the present invention.

In large scale fermenters fermentors, mammalian cells are particularly susceptible to sheer forces arising from the sparging of the vessel with gases and the mixing with the impeller. To minimise minimize the occurrence of cellular damage it is advantageous for the medium to contain a cell protectant such as polyethylene glycol, polyvinyl alcohols or pluronic polyols. Of these, Pluronic® (polyol, BASF Wyandotte Corp.) polyol F68 is preferred since unlike polyvinyl alcohols this is a non-toxic substance and unlike polyethylene glycols does not interfere with downstream purification.

Further improvements in CHO cell growth may be obtained by supplementing the medium with a peptide digest, hydrolysates or extracts, such as Tryprone, casein hydrolysate, yeast extract, or preferably papain digested soya peptone. The preferred amounts are 1%-0.025% w/v, most preferably 0.25% w/v.

The media of the invention for culturing recombinant CHO cells are capable of supporting the growth and secretion of product from such cells in suspension in small and large scale fermenters fermentors, static cultures and/or spinners. The culture medium according to the invention is also capable of supporting growth of cells at high cell density namely greater than 1×105 cells/ml up to or greater than 1.5×106 cells/ml and product secretion of 30 mg/l up to greater than 150 mg/l. The medium according to the invention is also capable of supporting this growth and product secretion over multiple passages lasting upto or greater than 6 months.

The medium is preferred for the production of all types of antibodies natural and altered. The invention therefore includes production of human antibodies wherein the amino acid sequences of the heavy and light chains are homologous with those sequences of antibodies produced by human lymphocytes in vivo or in vitro by hybridomas. Also provided are hybrid antibodies in which the heavy and light chains are homologous to a natural antibody but are combined in a way that would not occur naturally. For example, a bispecific antibody has antigen binding sites specific to more than one antigen. The constant region of the antibody may relate to one or other of the antigen binding regions or may be from a further antibody. Altered antibodies, for example chimaeric antibodies have variable regions from one antibody and constant regions from another. Thus, chimaeric antibodies may be species/species chimaeras or class/class chimaeras. Such chimaeric antibodies may have one or more further modifications to improve antigen binding ability or to alter effector functioning. Humanised Humanized or CDR-grafted antibodies (EP 239400) are embraced within the invention, in particular Campath 1H (EP328404) (Campath is a TM of The Wellcome Foundation) also composite antibodies, wherein parts of the hypervariable regions in addition to the CDRs are tranferred transferred to the human framework. Additional amino acids in the framework or constant regions of such antibodies may be altered. The invention further includes the production of Feb Fab fragments which are roughly equivalent to the Y branch portions of the heavy and light chains; this includes incomplete fragments or fragments including part of the Fc region.

In a further aspect of the invention there is provided an engineered CHO cell adapted to grow in a medium according to the invention. In particular a CHO cell engineered to express proteins such as tissue plasminogen activator or antibodies as defined above. In particular the invention provides a dhfr- CHO cell line transfected with a gene encoding a biologically active protein and a dhfr selectable marker gene, adapted to grow in a culture medium according to the invention. The protein is preferably an antibody as defined above.

The ingredients of the culture medium may be added in any order but it is preferable to add the iron source and when used, tyrosine, last to avoid precipitation.

Accompanying Figures are for illustration only.

FIG. 1 shows growth of C1H 3D11* 44 in WCM5 (protein-free medium) in a 1 liter fermenter fermentor measured as cell count/ml over 90 days.

FIG. 2 shows antibody production from C1H 3D11* 44 cells in WCM5 in a 1 liter formenter fermentor measured as micrograms of antibody/ml over 80 days.

EXAMPLE 1

Formulation for medium WCM4.

Medium A: (Iscoves modification of DMEM without BSA, transferrin and lecithin as set out in Table 1).

5 ml/liter +5 ml/liter 200 mM L glutamine +50 mg/liter L proline +50 mg/liter L threonine +50 mg/liter L methionine +50 mg/liter L cysteine +50 mg/liter L tyrosine +25 mg/liter ascorbic acid +0.062 mg · liter vitamin B6 +1.36 mg · liter vitamin B12 +0.2 mg/liter lipoic acid +0.088 mg/liter methyl linoleate +1 mg · lit methotrexate +1 IU/liter FeSO4 +1 IU/liter ZnSO4 +0.0025 μl/liter CuSO4 +5 mg/liter recombinant insulin (Nucellin) +50,000 Iu/liter polymyxin +20,000 Iu/liter neomycin +0.16 mg/liter putrescine-2 HCL

This medium does not contain hypoxanthine, thymidine or folinic acid which can bypass methotrexate selection. The medium does contain glycine which cannot by itself bypass selection. Therefore, this medium maintains full selection for methotrexate resistance.

EXAMPLE 2

Formulation for Medium WGM5 WCM5

Medmium Medium A: (Iscoves modification of DMEM without BSA, transferrin or lecithin).

+ 5 ml/liter 200 mM L glutamine + 50 mg/liter L proline + 50 mg/liter L threonine + 50 mg/liter L methionine + 50 mg/liter L cysteine + 50 mg/liter L tyrosine + 25 mg/liter L ascorbic acid + 0.062 mg · liter Vitamin B6 + 1.36 mg · liter Vitamin B12 + 2 mg/liter Ferric citrate + 1 mg/liter Zinc sulphate + 0.0025 mg · lit Copper sulphate + 50,000 IU/liter Polymyxin + 20,000 IU/liter Neomycin + 3 μl/liter Ethanolamine + 0.16 mg/liter Putrescine + 5 mg/liter Recombinant Insulin (Nucellin ®)

EXAMPLE 3

Growth of and Production from C1H 3D11* 44 in WCM4

C1H 3D11* cells are genetically engineered CHO DUK B11 cells (Urlaub and Chasin PNAS ( 1980,) PNAS 77, 7 pp 4216-4220). CHO DUK B11 cells cannot produce dihydrofolate reductase (dhfr). These cells were engineered to produce a humanised humanized IgG antibody, Campath 1H (Winter et al., Nature, 1988, 322, 323-327), using plasmid constructs to express heavy and light antibody chains and the mouse dhfr. Expression is amplified and maintained using the folate antagonist methotrate methotrexate. C1H 3D11* cells growing as a mono-layer in Isover+10% FBS Flow, non-essential amino acids, 10−6M Methotrexate and antibiotics were approximately 90% confluent. These cells were removed from the plastic with trypsin/versene, washed in Iscoves medium without supplements, centrifuged and resuspended at 5×104/ml in WCM4 medium+0.25% peptone+0.1% polyethylene glycol (PEG) 10,000+0.5% fetal bovine serum (FBS) without methotrexate (MTX). Three 25 cm2 cm3 flasks were set up with 10 ml of cell suspension+hypoxanthine (H), thymidine (T) or HT. These flasks were incubated at 36.5° C. in 5% CO2 incubator.

After six days, the flasks were pooled and added to an equal volume of WCM4+MTX without peptone or PEG, and were transferred to a 75 cm2 flask.

These cells were used to seed a 500 ml Techner spinner, incubated at 36.5° C. spinning at 40 rpm. Cells continued growing serum free for a period of over five months and although it was-found that the cells needed a period of adaptation, the growth rate and viability steadily improved. The population doubling time was calculated to be 73.1 hours over approximately 7 weeks; this decreased to 47.4 hours over the subsequent 20 days then stabilised. Antibody secretion remained high at levels in excess of 60 μg/ml. It was determined that the gene copy number in these cells did not decrease according to band intensity using Northern blot analysis.

In fermenters fermentors, these cells produced antibody in excess of 70 μg/ml and regularly achieved levels of 100 μg/ml or more. The cells are denoted C1H 3D11* 44.

EXAMPLE 4

Growth and Production of CIH C1H 3D11* 44 in WCM5 in a 1 liter fermenter fermentor.

C1H 3D11*44 cells from Example 3 which had been growing serum-free for over 2 months were transferred to a SGi 1 liter fermenter fermentor with a stainless steel angled paddle turning at 70 rpm. The temperature was set at 37° C., dO2 at 10% and pH control to 7-7.2. The fermenter fermentor was seeded on day 0 with 0.22×106 cells/ml in WCM4 (Example 1) with 0.1% polyethylene glycol (PEG) 10,000 and 0.25% soy peptone, and was top gassed with O2.The cells were routinely passaged using fresh medium and a split rate typically between 1 to 2 and 1 to 4.

On day 33 the top gassing was replaced with deep sparging which is can be expected to cause more physical damage to the cells.

On day 50 onwards WCM5 (Example 2) was used together with peptone and PEG instead of WCM4.

On day 53 the PEG was replaced with 0.1% Pluronic F68. The resulting growth and antibody levels achieved are shown in the the attached graphs (FIGS. 1 and 2), and demonstrate the capacity of the invention to allow protein-free production of antibody in excess of 100 μg/ml in fermenters fermentors.

EXAMPLE 5

Growth of CHO AJ19 MCB1 in WCM4 and compared to CHO AJ19 MCB1 grown in serum containing medium

Chinese hamster ovary cells, CHO AJ19 MCB1, derived from CHO DUK cells. (Urlaub & Chasin PNAS, 1980, 77, 7, pp 4216-4220, 1980 ), were genetically engineered to produce tPA under methotrexate selection. This cell line had been routinely grown in a fermenter fermentor as a suspension culture using normal growth medium consisting of RPMI 1640 medium (GIBCO), 2.5% acid hydrolysed hydrolyzed adult bovine serum (Imperial), 0.5% Tryptone, 50 IU/ml polymycin, 20 IU/ml neomycin, 500 nM methotrexate (MTX).

Medium WCM4 was formulated to which was added:

    • 46B 0.25% w/v N-Z Soy Peptone (Sigma P1265), 0.1% w/v Polyethylene glycol (PEG) 20,000 (Serva, Carbowax® 20M). 1 uM MTX.
    • 46C 0.25% w/v Yeast extract (Sigma Y0500), 0.1% w/v PEG 20,000 1 uM MTX. In this medium the Iscoves' in CM4 was replaced by RPMI 1640 medium (ICN FLOW).
    • 46D 0.25% w/v Yeast extract, 0.1% w/v PEG 20,000, 1 uM MTX.
    • 46E 0.25% w/v Yeast extract, 0.1% w/v PEG 20,000, 0.25% Fetal bovine serum (Imperial), 1 uM MTX.

The yeast extract, Peptone and PEG were made up as 10% w/v solutions with water (Wellcome media production unit) and filtered through a 0.2 um disposable filter (Gelman, Supor Vac), then diluted for use. The cells were incubated at 37° C. in a humidified incubator containing 5% CO2.

Cells growing in normal growth medium were pelleted by centrifugation at 1200 g +4° C. for 5 minutes, were washed in RPMI 1640 without supplements and pelleted again. The cells were then resuspended at 105 cell/ml in normal growth medium (46A) and the other media (46B, 46C, 46D or 46E). 24 well plates (Costar 16 mm wells) were seeded with 1 ml/well and incubated, at 37° C. in an incubator containing 5% CO2. On days 3, 4, 5 and 6 one well of each was counted using a haemcytometer and trypan blue exclusion. Two further wells of each were harvested, pooled and pelleted at 1200 g +4° C. 5 minutes. The supernatant was separated and stored at −20° C. These samples were subsequently assayed for tPA. On day 6 samples from 46A and 46D only were harvested.

RESULTS

tPA specific activities in various crude harvests

Crude material produced in the five different media were tested using a QA validated ELISA assay to measure the tPA antigen concentrations μg/ml using binding to a polyclonal antibody against tPA, and clot lysis assay to measure tPA activity in IU/ml. From these results (Table 2), the specific activities were calculated.

TABLE 2 MEAN tPA MEAN tPA DAYS ACTIVITY CONTENT SPECIFIC IN CELLCOUNT ×10−5 IU/ml ug/ml ACTIVITY EXPERIMENT CULTURE VIABLE NONVIABLE (n = 3) (n = 3) MegIU/mg 46A 3 3.5 0.1 3051 10.51 0.290 46A 4 3.7 0.3 4841 14.85 0.326 46A 5 4.1 0.2 5306 15.52 0.335 46A 6 5.8 0.5 8235 23.22 0.355 46B 3 5.2 0.1 2552 10.44 0.244 46B 4 7.2 0.3 5310 18.58 0.286 46B 5 7.8 0.2 6230 22.19 0.281 46C 3 3.8 0.2 2779 9.61 0.289 46C 4 4.9 0.3 3536 16.54 0.214 46C 5 5.6 0.3 4639 19.88 0.233 46D 3 7.5 0.2 4650 17.66 0.263 46D 4 8.3 0.8 7369 25.99 0.285 46D 5 7.4 1.0 7882 24.26 0.325 46D 6 6.1 2.0 8095 27.06 0.299 46E 3 6.4 0.1 6262 23.85 0.263 46E 4 7.3 0.5 10180 29.70 0.343 46E 5 6.1 1.3 9080 34.25 0.265

From the above table there was no change of the specific activity in the five different crudes. The yield of tPA from protein free medium B, C and D was nearly equal to the yield of tPA from standard growth medium in group A and E.

Example 6 Continuous growth of CHO AJ19 MCBI in WCM4

CHO AJ19 MCBI in WCM4 cells growing in normal growth medium were pelleted and washed as in Example 5 and were resuspended at 7×104/ml in 500 ml of medium 46B. These cells were transferred to a Techne spinner flask and incubated, as above, stirring at 40 rpm. At various time intervals the cells were counted and subcultured using the same medium. A sample was taken for tPA assay and treated as in Example 5.

The specific activity of tPA in various cell subcultures

The specific activity of supernatants from different pass levels of cells grown in WCM4 with peptone and 0.1% PEG 20K were measured by a combination of ELISA and clot lysis assay. The specific activities of different cell passages are summarised in Table 3.

TABLE 3 tPA present in supernatant tPA conc. ACTIVITY SPECIFIC CELLCOUNT ×10−5 SPLIT ug/ml IU/ml ACTIVITY DAYS PASS VIABLE NONVIABLE RATE (n = 3) (n = 3) Meg.U/mg 7 1 9.75 0.65  1-10 ND ND ND 10 2 4.95 0.01 1-5 ND ND ND 13 3 6.35 0.0  1-10 22.2 8865 0.399 16 4 3.8 0.0  1-10 7.25 1914 0.264 21 5 7.2 0.8  1-10 15.08 4331 0.287 24 6 4.1 0.3  1-10 8.28 2040 0.246 30 7 5.3 0.4 1-6 7.30 2052 0.281 34 8 5.2 0.32 — 13.65 3518 0.256 36 8 7.95 0.10 1-8 18.60 5327 0.286 37 8 ND ND — 20.68 5526 0.267 38 8 100% — 19.10 5474 0.287 38 9 12.00 0.5 1-5 20.85 8348 0.400 43 10 5.5 0.12 1-5 7.38 1888 0.256 48 11 4.4 0.19 1-6 13.4 3143 0.235 12 Experiment terminated ND = not done.

Over a 48 day period, base on the above split rate, one cell could have divided to give 3.77×108 cells. This is equivalent to 31.8 population doublings with a doubling time of 36 hours.

The results of the experiments conducted in Examples 5 and 6 demonstrate that the serum free media of the present invention is capable of supporting cell growth and tPA yield comparable to that achieved in serum containing media.

Claims

1. A method for growing genetically engineered CHO cells which comprises in suspension comprising the step of:

culturing genetically engineered CHO cells in suspension under cell growing conditions effective to support secretion of a product from the genetically engineered CHO cells over multiple passages for at least 20 days, wherein the cell growing conditions are characterized as:
in the absence being free of both serum and transferrin; and
in comprising a medium comprising water, an osmolality regulator, a buffer, an energy source. L-glutamine and at least one additional amino acid, an inorganic, organic or recombinant iron source and a recombinant or synthetic growth factor wherein each component of said medium is obtained from a source other than directly from an animal source.

2. A The method for culturing growing CHO cells in accordance with claim 1, wherein the medium further comprises at least one component selected from the group consisting of: non-ferrous metals, vitamins or and cofactors.

3. A The method for culturing growing CHO cells in accordance with claim 1, wherein the osmolality regulator maintains the medium at 200-350 mOsm.

4. A The method for culturing growing CHO cells in accordance with claim 1, wherein the medium is maintained at a pH in the range of about 6.5 to about 7.5 by the buffer.

5. A The method for culturing growing CHO cells in accordance with claim 1, wherein the concentration of the energy source is within the range of 1000-10,000 mg/liter.

6. A The method for culturing growing CHO cells in accordance with claim 5, wherein the energy source is a monosaccharide.

7. A The method for culturing growing CHO cells in accordance with claim 1, wherein the additional amino acids are selected from the group consisting of L-alanine, L-arginine, L-asparagine, L-aspartic acid, L-cystine cysteine, L-glutamic acid, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine and L-valine.

8. A The method for culturing growing CHO cells in accordance with claim 1, wherein the concentration of L-glutamine is within the range of 400-600 mg/liter.

9. A The method for culturing growing CHO cells in accordance with claim 2, wherein the medium further comprises a lipid factor in an amount of 0.05-10 mg/liter.

10. A The method for culturing growing CHO cells in accordance with claim 1, wherein the iron source is an inorganic ferric or ferrous salt which is provided in a concentration of from 0.25-5 mg/liter.

11. A The method for culturing growing CHO cells in accordance with claim 1, wherein the growth factor comprises is selected from the group consisting of: recombinant or synthetic insulin, platelet derived growth factor, thyroxine T3, thrombin, interleukin, progesterone, hydrocortisone or and vitamin E.

12. A The method for culturing growing CHO cells in accordance with claim 11 1, wherein the growth factor is recombinant or synthetic insulin.

13. A The method for culturing growing CHO cells in accordance with claim 1, wherein the medium further comprises at least one component selected from the group consisting of: a peptide digest, peptide hydrolysate or and peptide extract.

14. A method for culturing cells in accordance with claim 1, A method for growing genetically engineered CHO cells in suspension, comprising the step of:

culturing genetically engineered CHO cells in suspension under cell growing conditions effective to support secretion of a product from the genetically engineered CHO cells over multiple passages for at least 20 days, wherein the cell growing conditions are characterized as:
being free of both serum and transferring; and
comprising a medium comprising water, an osmolality regulator, a buffer, an energy source, L-glutamine, and at least one additional amino acid, an inorganic, organic or recombinant iron source and a recombinant or synthetic growth factor, wherein each component of said medium is obtained from a source other than directly from an animal source, wherein the medium is essentially free of hypoxanthine and thymidine.

15. A The method for culturing growing CHO cells in accordance with claim 14, wherein the medium further comprises methotrexate.

16. A method for culturing growing genetically engineered CHO cells which comprises in suspension comprising the step of:

culturing and growing Chinese hamster ovary genetically engineered CHO cells in suspension under cell growing conditions effective to support secretion of a product from the genetically engineered CHO cells over multiple passages for at least 20 days, wherein the cell growing conditions are characterized as:
in the absence being free of both serum and transferrin;
in comprising a medium comprising:
an osmolality regulator to maintain the osmolality of the medium within the range of about 200-350 mOsm,
a buffer to maintain the pH of the medium within the range of about 6.5 to 7.5,
about 1000-10,000 mg of a monosaccharide,
about 400-600 mg of L-glutamine,
about 10-200 mg of at least one amino acid selected from the group consisting of L-alanine, L-arginine, L-asparagine, L-aspartic acid, L-cystine cysteine, L-glutamic acid, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine and L-valine,
about 0.25-5 mg of an inorganic or recombinant iron source,
about 5 μg-5 mg of a recombinant or synthetic insulin,
and sufficient water to provide one liter of medium.

17. A method for culturing CHO cells which comprises culturing and growing Chinese hamster ovary cells in the absence of serum in a medium comprising

a base medium containing the amino acids, non-ferrous metal ions, vitamins and cofactors essentially as set forth in Table 1,
an osmolality regulator selected from NaCl, KCl, and KNO3 in an amount sufficient to maintain the osmolality of the medium within the range of about 200-350 mOsm,
at least one buffer selected from CaCl2.2H2O, MgSO4.7H2O, NaH2PO4.2H2O, sodium pyruvate, N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulphonic acid (HEPES) and 3-[N-morpholino]-propanesulfonic acid (MOPS) in an amount sufficient to maintain the medium within the pH range of about 6.5-7.5,
about 1000-10,000 mg of mannose, fructose, glucose or maltose,
about 5 ml of 200 mM L-glutamine,
about 50 mg each of L-proline, L-threonine, L-methionine, L-cysteine and L-tyrosine,
about 20-50 mg of L-ascorbic acid,
about 0.01-0.5 mg each of Vitamin B6 and Vitamin B12,
about 0.25-5 mg of a ferric or ferrous salt,
about 1 mg of zinc sulfate,
about 2.5 μg of copper sulfate,
about 10,000-100,000 IU of at least one antibiotic selected from the group consisting of polymyxin, neomycin, penicillin and streptomycin,
about 3 μl of ethanolamine,
about 0.01-1.0 mg of putrescine,
about 5 μg-5 mg of recombinant insulin and sufficient water to comprise one liter of medium; wherein each component of said medium is obtained from a source other than directly from an animal source.

18. A The method for growing CHO cells in accordance with claim 1, wherein each component of the medium is selected from at least one source selected from the group consisting of: an inorganic, synthetic, recombinant, plant or and bacterial source.

19. A method for growing genetically engineered CHO cells in suspension, comprising the step of:

culturing genetically engineered CHO cells in suspension at a density greater than 1×105 cells/mL under cell growing conditions effective to support secretion of a product from the genetically engineered CHO cells over multiple passages for at least 20 days, wherein the cell growing conditions are characterized as:
being free of both serum and transferrin; and
comprising a medium comprising water, an osmolality regulator, a buffer, an energy source, L-glutamine and at least one additional amino acid, an inorganic, organic or recombinant iron source and a recombinant or synthetic growth factor, wherein each component of said medium is obtained from a source other than directly from an animal source.

20. The method for growing CHO cells in accordance with any one of claims 1 to 16, 18, or 19, wherein said culturing results in secretion of said product from the genetically engineered CHO cells into said medium.

21. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 30 days.

22. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 40 days.

23. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 50 days.

24. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 60 days.

25. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 70 days.

26. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 80 days.

27. The method according to any one of claims 1 to 16, 18 or 19, wherein said method results in growth of said genetically engineered CHO cells in suspension and secretion of said product over multiple passages for at least 6 months.

28. A method for growing genetically engineered CHO cells in suspension, comprising the step of:

culturing genetically engineered CHO cells in suspension at a density greater than 1×105 cells/mL under cell growing conditions effective to support secretion of a product from the genetically engineered CHO cells over multiple passages for at least 20 days, wherein the cell growing conditions are characterized as:
being free of both serum and transferrin; and
comprising a medium comprising water, an osmolality regulator, a buffer, an energy source, L-glutamine and at least one additional amino acid, an inorganic, organic or recombinant iron source and a recombinant or synthetic growth factor, wherein each component of said medium is obtained from a source other than directly from an animal source,
wherein said culturing results in secretion of at least 30 mg/L of said product from the genetically engineered CHO cells into said medium.

29. The method according to claim any one of claims 1 to 16, 18, 19, or 28, wherein said genetically engineered CHO cells are dhfr− CHO cells.

30. The method for growing CHO cells in accordance with any one of claims 14, 16, 19, or 28 wherein the medium further comprises at least one component selected from the group consisting of: non-ferrous metals, vitamins and cofactors.

31. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the osmolality regulator maintains the medium at 200-350 mOsm.

32. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the medium is maintained at a pH in the range of about 6.5 to about 7.5 by the buffer.

33. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the concentration of the energy source is within the range of 1000-10,000 mg/liter.

34. The method for growing CHO cells in accordance with claim 33, wherein the energy source is a monosaccharide.

35. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the additional amino acids are selected from the group consisting of L-alanine, L-arginine, L-asparagine, L-aspartic acid, L-cysteine, L-glutamic acid, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine and L-valine.

36. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the concentration of L-glutamine is within the range of 400-600 mg/liter.

37. The method for growing CHO cells in accordance with any one of claims 14, 16, 19, or 28, wherein the medium further comprises a lipid factor in an amount of 0.05-10 mg/liter.

38. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the iron source is an inorganic ferric or ferrous salt which is provided in a concentration of 0.25-5 mg/liter.

39. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the growth factor is selected from the group consisting of: recombinant or synthetic insulin, platelet derived growth factor, thyroxine T3, thrombin, interleukin, progesterone, hydrocortisone and vitamin E.

40. The method for growing CHO cells in accordance with any one of claims 14, 19, or 28, wherein the growth factor is recombinant or synthetic insulin.

41. The method for growing CHO cells in accordance with any one of claims 14, 16, 19, or 28, wherein the medium further comprises at least one component selected from the group consisting of: a peptide digest, peptide hydrolysate and peptide extract.

Referenced Cited
U.S. Patent Documents
4205126 May 27, 1980 Cartaya
4657866 April 14, 1987 Kumar
4767704 August 30, 1988 Cleveland
4929706 May 29, 1990 Heifetz et al.
5019499 May 28, 1991 Murakami et al.
5045468 September 3, 1991 Darfler
5063157 November 5, 1991 Stockinger
5122469 June 16, 1992 Mather et al.
5135866 August 4, 1992 Heifetz et al.
5232848 August 3, 1993 Wolfe et al.
5316938 May 31, 1994 Keen et al.
5545403 August 13, 1996 Page et al.
5545404 August 13, 1996 Page et al.
5545405 August 13, 1996 Page et al.
5633162 May 27, 1997 Keen et al.
5807715 September 15, 1998 Morrison et al.
5846534 December 8, 1998 Waldmann et al.
5876961 March 2, 1999 Crowe et al.
6100061 August 8, 2000 Reiter et al.
RE40070 February 19, 2008 Shandle et al.
20040259838 December 23, 2004 Joyce et al.
Foreign Patent Documents
0 164 813 June 1985 EP
0 248 656 June 1987 EP
0229530 July 1987 EP
0239400 September 1987 EP
0 274 394 January 1988 EP
0 307 248 September 1988 EP
0307247 March 1989 EP
0314161 May 1989 EP
0316068 May 1989 EP
0325190 July 1989 EP
0328404 August 1989 EP
0 363 703 September 1989 EP
0389786 October 1990 EP
0390327 October 1990 EP
0404003 December 1990 EP
0481791 April 1992 EP
0 523 949 July 1992 EP
0513738 December 1992 EP
0610447 April 1993 EP
0 481 790 February 1999 EP
0388151 March 1999 EP
0 822 255 June 2004 EP
2543158 September 1984 FR
2196348 April 1988 GB
61025480 July 1984 JP
63-192381 August 1988 JP
S63-7780 January 1998 JP
WO 87/00195 January 1987 WO
WO 87/01131 February 1987 WO
WO 88/00967 February 1988 WO
WO 89/00999 February 1989 WO
WO 90/03429 April 1990 WO
WO 91/04336 April 1991 WO
WO 91/10722 July 1991 WO
WO 92/07084 April 1992 WO
WO 93/02108 February 1993 WO
WO 93/07899 April 1993 WO
WO 01/51615 July 2001 WO
Other references
  • Hayter et al. “Recombinant Gamma-Interferon Production by CHO cells in Serum-free Medium.” Advances in Cell Biology and Technology Bioprocessing. RE Spier et al (eds). Butterworths: Kent, England, 1989, pp. 280-282.
  • Feys et al, Int J Cancer, 1988, Supplement 2, pp. 26-27.
  • Hamilton et al, in Vitro, 1977, vol. 13, No. 9, pp. 537-547.
  • Urlaub et al, Proceedings of the National Academy of Sciences of The United States of America, 1980, vol. 77, No. 7, pp. 4216-3220.
  • Michel, et al., Proceedings of the National Academy of Sciences, vol. 81 (24) pp. 7708-7712 (1984).
  • Zettlemeissl, et al., Journal of Biological Chemistry, vol. 264 (35) pp. 21153-21159 (1989).
  • Sano et al., Cell Structure and Function, vol. 13 (2) pp. 143-159 (1988).
  • Scanhill et al., Proceedings of the National Academy of Sciences, vol. 80 pp. 4654-4658 (1983).
  • Schneider & Laviox, Journal of Immunological Methods, vol. 129 pp. 251-268 (1990).
  • Schnider, Journal of Immunological Methods, vol. 116 pp. 65-77 (1989).
  • Sertich, et al., Journal of Cellular Physiology, vol. 127 pp. 114-120 (1986).
  • Spira et al., Trends in Animal Cell Culture Technology, Proc. Ann. Meeting Jpn. Tech., pp. 67-73 (1990) [Reporting conference meeting in 1989].
  • Takagi, et al., Journal of Bioscience and Bioengineering, vol. 90(5) pp. 509-514 (2001).
  • Taylor et al., Mutation Research, vol. 67 pp. 65-80 (1979).
  • Thilly, et al., Mammalian Cell Technology, pp. 26-29 (1986).
  • Titeux et al., Journal of Cellular Physiology, vol. 121 pp. 251-256 (1984).
  • Tsujimoto et al., Journal of Biochemistry, vol. 106 pp. 23-28 (1989).
  • Ungemach et al., The 50th Meeting of the joint FAO/WHO Expert Committee on Food Additives (JECFA), World Health Organization, 1998.
  • Urban & Chasin, Proceedings of the National Academy of Sciences, vol. 77(7) pp. 4216-4220 (1980).
  • Weber et al., Journal of Neuroimmunology, vol. 22 pp. 1 to 9 (1989).
  • Weidle et al., Gene, vol. 51 pp. 21-29 (1987).
  • Weidle et al., Gene, vol. 60 pp. 205-216 (1987).
  • Whitaker et al., Biopharm, vol. 3 (8) p. 5 (Sep. 1990).
  • Whittle et al., Protein Eng., vol. 1 pp. 499-505 (1987).
  • Wiebe et al., ESACT 9th Meeting, Editors Spier R.E. et al., pp. 68-71 (1989).
  • Wood, et al, Journal of Immunology, vol. 145 pp. 3011-3016 (1990).
  • Yang et al., Proceedings of the National Academy of Sciences USA, vol. 81 pp. 2752-2756 (1984).
  • Zekauskas et al., J. Okla. State Med. Assoc. vol. 83 pp. 447-448 (1990).
  • Zettlemeissl et al., Biotechnology, vol. 5 pp. 720-725 (1987).
  • McCormick et al., Molec. Cell Biol., vol. 4 (1) pp. 166-172 (1984).
  • McKeehan et al., Proceedings of the National Academy of Sciences USA, vol. 73 pp. 2023-2027 (1976).
  • Mendiaz et al., In Vitro Cell. Dev. Biol., vol. 22 pp. 66-74 (1986).
  • Merten et al., Production of biologicals from animal cells in culture research, development, and achievements, 10th Mfg., Avignon, France (1990).
  • Morrison et al., PNAS, vol. 81 pp. 6851-6855 (1984).
  • Mountain and Adair, Biotechnology and Genetic Engineering Reviews, vol. 10 pp. 1-142 (1992).
  • Murphy, Science, vol. 273 (5276 pp. 746-747 (1996).
  • Nakamori et al., Applied and Environmental Microbiology, vol. 64 (5) pp. 1607-1611 (1998).
  • Neuberger et al., Nucleic Acids Research, vol. 16(14) pp. 6713-6724 (1988).
  • Newman, et al., Biotechnology, vol. 10 pp. 1455-1460 (1992).
  • Nippon Zenyaku Industries, Reply of Applicant concerning EP92306420.8, May 28, 1998.
  • Noda et al., Chem. Abs., vol. 110 (19) Abstract p. 652 (1988).
  • Ogata et al., Applied Mcrobiology Biotechnology, vol. 38 (4) pp. 520-525 (1993).
  • Oka et al., Bioprogress Technol., vol. 10 pp. 72-92 (1990).
  • Organic Chemistry, John Wiley & Sons Inc, vol. II Second Edition pp. 1129-1130 and 1136-1138 (1943).
  • Page and Sydenham, Biotechnology, vol. 21 (10) pp. 64-68 (1991).
  • Page et al., Biotechnology, vol. 9 pp. 64-68 (1991).
  • Pearson et al., The 19th Meeting of the European Society for Animal Cell Technology, pp. 1-11 (2005).
  • Persson et al. PNAS, vol. 88 pp. 2432-2436 (1991).
  • Phillpotts, Cytotechnology, vol. 2 pp. 161-162 (1989).
  • R.H. Kimberlin, Symposium of Virological Aspects of the Safety of Biological Products London, England 1990, Develop. Biol. Standard, vol. 75 pp. 75-82 (1991).
  • Rabbi S. Emanuel, MK Vaad Hair, vol. IV (7) 9 pgs (2003) <www.mk.ca/page6_11.php>.
  • Regenstein et al., E-Journal <www.Kashrut.com>, Kosher Issues for Today's Dairy Industry, 2002.
  • Riechmann et al., Nature, vol. 322, pp. 323-327 (1988).
  • Robinson et al., Human Antibody Hybridomas, vol. 2 pp. 84-92 (1991).
  • Rose et al., Molecular Immunology, vol. 29(1) pp. 131-144 (1992).
  • Rüker, et al., Annals New York Acad. Sci., pp. 212-219 (1991).
  • Saban, T., (2004) “Food Additives From Islamic Perspective,” Version 1.3 <wwwsrvl.mycity.at/privat.9704236/Im/LM-en.html>.
  • Sakar, et al., Proceedings of the National Academy of Science, vol. 92 pp. 3323-3327 (1995).
  • Salahuddin et al., Journal of Experimental Medicine, vol. 155 pp. 1842-1857 (1982).
  • Sambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition pp. 8.8-8.9 (1989).
  • Sano et al., Cell Struct. Funct., vol. 13 (2) pp. 142-159 (1988).
  • Hale et al., Mol. Biol. Med., vol. 1 pp. 305-319 (1983).
  • Hale et al., The Lancet, vol. 2 pp. 1394-1399 (1988).
  • Hale et al., Tissue Antigens, vol. 35 pp. 118-127 (1990).
  • Hale et al., Transplantation, vol. 45 pp. 753-759 (1988).
  • Ham, Proceedings of the National Academy of Sciences, vol. 53 pp. 288-293 (1965) [composition of F12 attached].
  • Handa-Corrigan et al., Enzyme Microbial Technology, vol. 11 ppl. 230-235 (1989).
  • Higuchi, K., Advances Applied Microbiology, vol. 16 pp. 111-136 (1973).
  • Holtta et al., Biochemica et Biophysica Acta, vol. 721 pp. 321-327 (1982).
  • I5500, Biochemicals and Reagents for Life Science Research, p. 1147 (2002-2003) Sigma-Aldrich Company (Current website information also included).
  • Isaacs et al., The Lancet, vol., 340 (8822) pp. 748-752 (1992).
  • Iscove and Melchers, The Journal of Experimental Medicine, vol. 147 pp. 923-933 (1978).
  • K. Loren, Vibrant Life, vol. 2 (1) 13 pgs (1999).
  • Kaqawa et al., Journal of Biochemistry, vol. 68 pp. 133-136 (1970).
  • Katsua & Takaoka, Methods of Cell Biology, vol. 6 pp. 1-42 (1973).
  • Katsuta and Takaoka, Journal of Experimental Medicine, vol. 30 pp. 235-259 (1960).
  • Katsuta and Takaoka, Methods of Cell Biology, vol. 6 pp. 1-42 (1973).
  • Kaufman et al., Molec. Cell Biol., vol. 5(7) pp. 1750-1759 (1985).
  • Keay, Biotechnology and Bioengineering, vol. XVIII pp. 363-382 (1976).
  • Kim, et al., In Vitro Cell Dev. Biology, vol. 38 pp. 314-319 (2002).
  • King, et al., Biochem Journal, vol. 281 pp. 317-323 (1992).
  • Knight et al., Human Antibody Hybridomas, vol. 3 pp. 129-136 (1992).
  • Köhrle, J., Biochimie, vol. 81 pp. 527-533 (1999).
  • Kurano, et al., Journal of Biotechnology, vol. 15 pp. 101-112 (1990).
  • Kyle et al., Journal of Rheumatology, vol. 18 (11) pp. 1737-1738 (1991).
  • Larrick, et al., Biotechnology, vol. 7 pp. 934-938 (1989).
  • Levy et al., Gene, vol. 54 pp. 167-173 (1987).
  • Lewis et al., Human Antibody Hybridomas, vol. 3 pp. 146-152 (1992).
  • Liu et al., J. Immunology, vol. 13(10) pp. 3521-3528 (1987).
  • Liu, et al., Gene, vol. 54(1) pp. 33-40 (1987).
  • Liu, et al., PNAS, vol 84(10) pp. 3439-3433 (1987).
  • Luff, cited in “The BSE Inquiry,” established fot the British Government.
  • Marquis et al., Cytotechnology vol. 2 pp. 163-170 (1989).
  • Mather, et al., Methods of Enzymology, vol. 185 pp. 567-577 (1995).
  • C6852, Biochemicals and Reagents for Life Science Research, p. 600 (2002-2003) Sigma-Aldrich Company (Current website information also included).
  • C7880, Biochemicals and Reagents for Life Science Research, p. 600 (2002-2003) Sigma-Aldrich Company (Current website information also included).
  • C8503, Biochemicals and Reagents for Life Science Research, p. 508 (2002-2003) Sigma-Aldrich Company (Current website information also included).
  • Carter et al., PNAS, vol. 89 pp. 4285-4289 (May 1992).
  • Colcher et al., Cancer Research, vol. 49 pp. 1738-1745 (1989).
  • Dafler, F., In Vitro Cell Dev. Bio., vol. 26 pp 769-778 (1990).
  • Darfler, In Vitro Cell. Dev. Bio., Vo 26 pp. 779-783 (1990).
  • DeCourcy et al., Experimental Cell Research, vol. 192 pp. 52-60 (1991).
  • DeWaele et al., European Journal of Biochemistry, vol. 176 (2-3) pp. 287-295 (1988).
  • Dickman, Nature, vol. 329 p. 93 (1987).
  • Dulbecco and Freeman, Virology, vol 8 pp. 396-397 (1959) [composition of DMEM attached].
  • Dyer et al., Blood, vol. 73 pp. 1431-1439 (1989).
  • Eagle, Science, vol. 130 pp. 432-437 (1959) [composition of MEM attached].
  • Ebert, Expression of Antibody C-DNA in CHO (“Chinese hamstet ovary”) Cells, Dissertation Completed at the Institute for Applied Microbiology University for Soil Cultivation , Feb. 1991 (with Translation).
  • Ehrlich et al., Molecular Immunology, vol. 28(4-5) pp. 319-322 (1991).
  • Ehrlich et al., Human Antibod. Hybridomas, vol. 1(1) pp. 23-26 (1990).
  • Feldman, G., (Oct. 2001), “Amino Acid Production and the Associated Theoretical Risk of BSE Transmission from their Use in the Production of Biologicals, Drugs, and Medical Devices,” FDA TSA Advisory Committee Meeting <www.fda.gov/Ohrms/dockets/ac/01/slides/.
  • Feys et al., International Journal of Cancer, vol. 2 pp. 26-27 (1988).
  • Feys, et al., Chemical Abstracts, vol. 108 (23) p. 514 (1988).
  • Fouser, et al., Biotechnology, vol. 10 pp. 1121-1127 (1992).
  • Freshney, Culture of Animal Cells, Second Edition, Wiley-Liss pp. 70-84 (1989).
  • Gaboriau, et al., Biochemical Pharmacology, vol. 67 pp. 1627-1637 (2004).
  • Gardner-Lane et al, Decision on Preliminary Motions, Glaxo Welcome Inc v. Cabilly et al, 2002.
  • Gasser et al., In Vitro Cellular Development Biology, vol. 21 (10) pp. 588-592 (1985).
  • Gillies et al., Biotechnology, vol. 7 pp. 799-804 (1989).
  • Gillies et al., J. Imminological Methods, vol. 125 pp. 191-202 (1989).
  • Goeddel et al., Proceedings of the National Academy of Sciences USA, vol. 76 (1) pp. 106-110 (1979).
  • Grady, et al., Journal of Biological Chemistry, vol. 284(34) pp. 20221-20220 (1989).
  • Hale et al., Journal of Immunological Methods, vol. 103 pp. 59-67 (1987).
  • 1990 GIBCO BRL Catalogue & Refernce Guide (confirmation of availability attached).
  • Abstract of the USPTO trademark database regarding the trademark for Nucellin of Eli Lilly.
  • Ahmed, S. (2001) “Eating Human Hair by Another Name?,” www.albalagh.net/hala/col2.shtml.
  • Ahrens, et al., Post Graduate Medicine vol. 80, pp. 181-187 (1988).
  • Anthony Lubinicki, ESACT 9th Meeting, Editors Spier R.E. et al., pp. 85-92 (1989).
  • Bebbington et al., Methods: A companion to Methods in Enzymology, vol. 2(2) pp. 136-145 (1991) Abstract.
  • Bobbington, et al., Biotechnology, vol. 10 pp. 169-175 (1992).
  • Biech Z., reprinted with permission from MK News and Views, vol. IV (6) 2003.
  • Brogden, et al., Drugs, vol. 34 pp. 350-371 (1987).
  • Brown et al., Emerging Infectious Diseases, vol. 7 (1) pp. 6-16 (2001).
  • U.S. Appl. No. 10/145,712, filed May 16, 2002, Page, et al.
  • U.S. Appl. No. 10/145,992, filed May 16, 2002, Page, et al.
  • U.S. Appl. No. 10/765,067, filed Jan. 28, 2004, Page, et al.
  • U.S. Appl. No. 90/006,997, filed Apr. 5, 2004, Crowe, et al.
  • Spellman, et al., Journal of Biological Chemistry, vol. 264(24) pp. 14100-14111 (1989).
  • Yan, et al., TIBS Jul. 14, 1989.
  • Rudd, et al., Molecular Immunology, vol. 28(12) pp. 1369-1378 (1991).
  • Paulson, TIBS Jul. 14, 1989.
  • Paulson and Colley, Journal of Biological Chemistry, vol. 264(30) pp. 17615-17618 (1989).
  • Mizouchi, et al., Biochem Journal, vol. 254 pp. 599-603 (1998).
  • Furukawa and Kotaba, Molecular Immunology, vol. 28 (12) pp. 133-1340 (1991).
  • Dijkmans, et al., Journal of Biological Chemistry, vol. 262(6) pp. 2528-2535 (1987).
  • Curling, et al., Biochem Journal, vol. 272 pp. 333-337 (1990).
  • Bullied, et al., Biochem Journal, vol. 268 pp. 777-781 (1990).
  • Colomb, et al., Boochem. J., vol. 145 pp. 177-183 (1985).
  • Prokop, et al., Editors, Annals of the New York Academic of Sciences, 646:Table of Contents and Prefaces, Dec. 27, 1991.
  • Hale, et al., The Lancet, vol. 332(8625) pp. 1394-1399 (1988).
  • U.S. Appl. No. 11/289,714, filed Nov. 29, 2005, Crowe, et al.
  • U.S. Appl. No. 11/804,729, filed May 18, 2007, Shadle, et al.
  • E-mail from Diane Fedyk in respect of GIBCO catalogue.
  • Examination Report of Apr. 1, 2005.
  • Response to Examination Report of Apr. 1, 2005.
  • Enlarged version of figure from Hamilton et al., In Vitro, vol. 13 (9) pp. 537-547 (1977.
  • Hata, et al., Cytotechnology (1992) vol. 10: pp. 9-14.
  • Haynes, et al., Nucleic Acids Res., 11, 687-706 (1983).
  • Kalwy, S., et al., “Toward More Efficient Protein Expression,” Molecular Biotechnology (2006) vol. 34 p. 151.
  • Kaufman, J. Mol. Biol., 159, 601-621 (1982).
  • Large Scale Mammalian Cell Culturetechnology, published by Marcel Dekker, Inc., and edited by A.S. Lubiniecki (pp. 161-175, 417-449 and 515-541; Sep. 14, 1990).
  • Neidhardt, et al., J. Bacteriol., 119, No. 3, 3, 736-747 (1947).
  • Opposition Division's Preliminary Opinion in respect of parent case (EP-B-0481791).
  • Opposition Division's Decision of revocation in respect of parent case (EP-B-0481791).
  • Patterson, et al., 1994: Appl Microbial Biotechnologiy 40: p. 691-698.
  • Morrison, “Trasfection Provide Novel Chimeric Antibodies,” Science (1985) 229:1202-1205.
  • Alsmadi et al. “Antibody-Dependant Cellular Cytotoxicity Directed against Cells Expreesing Human Immunodeficiency Virus Type 1 Envelope of Primary or Laboratory-Adapted Strains by Human and Chimpanzee Monoclonal Antibodies of Different Eptope Specificities”, Journal of Virology, 72(1),:286-293 (1998).
  • Forthal et al., “Antibody from Patients with Acute Human Immunodefciancy Virus (HIV) Infection Inhibitis Primary Strains of HIV in the presence of Natural-Killer Effector Cell”, Journal of Virology, 75(15):6953-6961 (2001).
  • English translation of Dissertation of Veronica Ebert Expression of Antibody c-DNA in CHO (Chinese Hamster Ovary) Cells University for Soil Conservation,Vienna Austria (1991).
  • Letter form head librarian of Boku submitted in Opposition of EP0523949.
  • Letter form head librarian to “whom it may concern” submitted in Opposition of EP0523949.
  • Expert declaration of Dr. Florian Ruker submitted in Opposition of EP0523949.
  • Alfred hahn's CV submitted in Opposition of EP0523949Email of Jan. 11, 2007 from Ingrid Haas submitted in Opposition of EP0523949.
  • Declaration of Dr. J Adair submitted in Opposition of EP0523949.
  • Roberts, et al. J.Cell Biochem 20th Annual Meeting p. 122 (2001).
  • Roitt Brostoff and Male, Immunology 6th edition, p. 74 (2001).
  • Jefferies. “Structure Function relationship in Human Immunoglobulans” neth J Med (1991), vol. 39, No. 3-4, pp. 188-198. Abstract only.
  • Patel, et al. “Different culture methods lead to differences in mrine IgG monoclonal antibody” Biochem J. 285, 839-845 (1992).
  • Kunert, et al. “Molecular Characteristics of Five Neutralizinf Anti-HIV Type I Antibodies: Indentification of Nonconventional D. Segments in the Human Monoclonal Antibodies 2G12 and 2F5” Aids Research 14(3):1115-1128 (1998).
  • Bartholomew, et al. “functional analysis of the effects of a fully humanized anti-Cd4 antibody on resting and activated human T cells”Immunology 85:41-48 (1995).
  • Sims, et al. “A Humanised CD18 Antibody can Block Fucntion without Cell Destruction” J. Immumol. 151:2296-2309 (1993).
  • Waldman, et al. “A Clonal Derivative of Tunicamysin-resiistant Chinese Hamster Ovary Cells with Increased N-Acetylglucosamine-Phosphate Transferase Activity Has Altered Asparagine-Linked Glycosylation” J. Cell. Physio. 131 pp. 302-317 (1987).
  • Aathoon and Birch, Science, (1986) 232: 1390-1395.
  • Barnes, Biotechniques, (1987) vol. 5, No. 6, pp. 534-542.
  • Bohak, et al., Biopolymers, (1987) 26:s205-213.
  • Broad, et al., In Vitro Cellular and Developmental Biology, (1986) 22 (2):66-74.
  • Buck, et al., J. Virol. Meth., (1985) 10:171-184.
  • Bulens, et al., Uer. J. Biochem., (1991) 195:235-242.
  • Castro, et al., Bitoech Appl. BioChem (1985) 21:57-100.
  • Chotigeat, et al., Cytotechnology (1994) 15:217-221.
  • Cini, et al., “Molecular Basic for the Isozymes of bovine Glucose-6-Phosphate Isomerase,” Arch Biochem. Biophys. 263(1) 96-106.
  • Curling, Biochem. J., (1990) 272:333-337.
  • Decision of Appeal of the European Patent Office dated Jan. 15, 2004 T0962/98—3.3.1 Appl. No. 94931395.1.
  • Decision of Boards of Appeal of the European Patent Office date Jan. 18, 2005 T0278/03—3.3.8 Appl. No. 91309595.6.
  • Decision of Boards of Appeal of The European Patent Office dated Sep. 23, 2004 T0720/02—3.4.2 Appl. No. 97200957.5.
  • Decision of Boards of Appeal of The European Patent Office dated Aug. 26, 2005 T0039/03—3.4.2 Appl. No. 99100131.4.
  • Decision of Technical Boards of Appeal 3.4.2 dated Jul. 13, 2004 T1158/01—3.4.2 Appl. No. 99126075.3.
  • Deeds, et al., “Creating a New Medium to Meet the Variable Nutritional Requirements of Chinese Hamster Ovary (CHO) Cell Clones.” Sigma Aldrich.com http://www.sigmaaldrich.com/sigma/general (Jul. 2003).
  • DiAugustine, et al. “Evidence of Isoaspartyl (Deamidated) Forms of Mouse Epidermal growth Factor.” Anal. Biochem. (1987) 165(2):420-429.
  • Dyer, et al., Leukemia and Lymophoma, (1989) 1:179-193.
  • Felgenhauer, et al. “Nucleotide sequences of the cDNAs encoding the V-regions of H-and L-chains for a human monocalonal antibody specific to HIV-1-gp41,” Nucleic Acids Research (1990) 18(16) 4927.
  • Huang and Gorman, “The Simina Virus 40 Small-t Intron, Present in May Common Expression Vectors, Lead to Aberrant Splicing,” Molecular and Cellular Biology (1990) 10(4):1805-1810.
  • J. Cell. Biochem, 20th Annual Meeting (1991):122.
  • Jenkins, et al., Nature Biotechnology, (1996) 14:975-980.
  • Jungbauger, et al., Pilot scale production of a human monoclonal antibody against human immunodeficiency virus HIV-1, Journal of Biological and Biophysical Methods. (1989) 19:223-240.
  • Kilburn, et al. Biotechnology and Bioengineering (1968) vol. X:801-814.
  • Leatherbarrow, et al., Imuunology (1985) 22(4):401-413.
  • Lipoldova, “T-cell receptor V beta 5 usage defines reactivity to9 a human T-call receptor monoclonal antobody,” Immunogenetics (1989) 30(3):162-8—abstract.
  • Madisen, et al., Growth Factors (1990) 3:129-138.
  • Meri & Bonsdorff, ency. Of Imm., Delves & Roidd (eds), (1998) pp. 617-619.
  • Mesa, et al., J. Interferon and Cytokine Res. (1995) 15:309-315.
  • Miyazaki, et al. “Production of Monoclonal antibodies against human erythropoietin and their use in purification of human urinary erythropoietin” J. Immunol Methods. (Oct. 1988) 26:113(2)261-7 Abstract.
  • Moellering, et al., “Electrophoretic Differences in Mab Expressed in Three Media.” BioPharm. (Feb. 1990) 30-38.
  • Morrison, “Transfection Provide Novel Chimeric Antibodies,” Science (1985) 229:1202-1205.
  • Nishimura, et al., Cancer research (1987) 47:999-1005.
  • Painter, Encyclopedia Of Immunology, Second Ed. Delves et al., (1998):1208-1211.
  • Parekh, et al., Nature 316:452-457 (1985).
  • Phillips, et al., Cytotherapy (2001) 3 (3):233-242.
  • Ray, et al., ann. NY Aca Sci., (1990) 589:443-457.
  • Ripka, et al., Archives of Biochemistry and Biophysics (Sep. 1986) 249(2):533-545.
  • Freshney, Culture of Animal Cells, a Manual of Basic Technique, pp. 71, 74. and 119-128, 1992.
  • Miyaji, et al., Expression of Human beta-interferon in Namalwa KJM-1 which was adapted to a serum-free medium., Cytotechnology vol. 3, pp. 133-140, 1990.
  • McCormick, F., et al. (1984), “Inducible expression of amplified human beta . . . ” Molec. Cell Biol. (4(1): 166-172.
  • Kaufman, R.J. et al. (1985), “Coamplification and coexpression of human tissue-type plasminogen . . . ” Molec. Cell Biol. 5(7):1750-59.
  • Urblan, G and L.A. Chasin (1980). “Isolation of Chinese hamster cell mutants . . . ” Proc. Natl. Acad. Sci. USA 77(7):4216-20.
  • Freshney, R.I. (1988). Culture of Animal Cells. Alan R. Liss. New York USA, pp. 70-83.
  • Chandler, Josseph P., Cultivation of mammalian cells in serum-free medium, American Biotechology Journal 8(1), pp. 18-28, Jan. 1990.
  • EPO Communication in Opposition against European Patent No. 02 003 143.1, dated Jul. 21, 2010.
Patent History
Patent number: RE41974
Type: Grant
Filed: Dec 15, 2006
Date of Patent: Nov 30, 2010
Assignee: GlaxoSmithKline LLC (Philadelphia, PA)
Inventors: Michael John Keen (Kent), Nicholas Timothy Rapson (Cambridge)
Primary Examiner: Allison M Ford
Attorney: Jason C. Fedon
Application Number: 11/640,428