Attenuated FNR Deficient Enterobacteria
The invention provides an attenuated enterobacterium comprising an attenuating mutation in the fnr gene, and optionally further comprising a heterologous nucleic acid encoding a foreign antigen. Also provided are pharmaceutical formulations comprising the attenuated enterobacteria of the invention. Further disclosed are methods of inducing an immune response in a subject by administration of an immunogenically effective amount of an attenuated enterobacterium or pharmaceutical formulation of the invention.
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This application claims the benefit of U.S. Provisional Application No. 60/831,821, filed Jul. 19, 2006, the disclosure of which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTIONThis invention relates to attenuated Fumarate-Nitrate Reductase (FNR) enterobacteria strains. In particular, this invention relates to attenuated FNR enterobacteria strains and methods of using the same to induce an immune response.
BACKGROUND OF THE INVENTIONSalmonella enterica serovar Typhimurium is a gram-negative facultative intracellular pathogen. Serovar Typhimurium infections usually result from ingestion of contaminated food or water. The organism generally targets and colonizes the intestinal epithelium of the host and causes gastroenteritis (i.e., salmonellosis). During a Salmonella infection, the growth phase and growth conditions of the organism are important in attachment, invasion, and the regulation of many of the virulence genes. Cells grown under limited oxygen concentrations are more invasive and adhere better to mammalian cells than do aerobically grown or stationary-phase cells. Salmonella invasion genes have been identified and localized. During infection, serovar Typhimurium must adapt to changes in [O2] encountered in the gastrointestinal tract of the host. In Escherichia coli, transitions from aerobic to anaerobic environments or vice versa, involve changes in a large number of genes. However, upon sudden reappearance of oxygen, these cellular processes must be reversed in a precise and orderly fashion to ensure the safe transition to the oxygenated environment. This complex regulatory system has been extensively studied in E. coli, where the DNA-binding protein FNR encoded by fnr, senses changes in [O2] and controls the expression of the different genes either alone or in cooperation with other regulators, e.g., ArcA.
SUMMARY OF THE INVENTIONThe present invention is based, in part, on the inventors' discovery that enterobacteria comprising an attenuating mutation in the fnr (Fumarate-Nitrate Reductase) gene have an avirulent (i.e., highly attenuated) phenotype. Thus, the present invention provides attenuated enterobacteria and methods of using the same as attenuated immunogenic compositions, attenuated vaccines and/or as attenuated vaccine vectors to induce an immune response against a heterologous antigen in a subject.
Accordingly, a first aspect of the invention provides a pharmaceutical composition comprising an attenuated enterobacterium comprising an attenuating mutation (e.g., deletion) in the fnr gene in a pharmaceutically acceptable carrier.
A further aspect of the invention provides an attenuated enterobacterium comprising an attenuating mutation (e.g., a deletion) in the fnr gene and, optionally, further comprising a heterologous nucleic acid sequence encoding a foreign antigen. In particular embodiments, the attenuated enterobacterium is present in a pharmaceutical composition in a pharmaceutically acceptable carrier.
A further aspect of the present invention is a method of inducing an immune response in a subject comprising administering to the subject an immunogenically effective amount of an attenuated enterobacterium comprising an attenuating mutation (e.g., a deletion) in the fnr gene. In embodiments of the invention, the attenuated enterobacterium is provided in a pharmaceutical composition further comprising a pharmaceutically acceptable carrier. In further embodiments of the invention, the attenuated enterobacterium comprises a heterologous nucleic acid encoding a foreign antigen.
The invention further provides for the use of an attenuated enterobacterium or pharmaceutical composition of the invention to induce an immune response in a subject.
These and other aspects of the invention are set forth in more detail in the following description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is explained in greater detail below. This description is not intended to be a detailed catalog of all the different ways in which the invention may be implemented, or all the features that may be added to the instant invention. For example, features illustrated with respect to one embodiment may be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from that embodiment. In addition, numerous variations and additions to the various embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure, which do not depart from the instant invention. Hence, the following specification is intended to illustrate some particular embodiments of the invention, and not to exhaustively specify all permutations, combinations, and variations thereof.
All publications, patents, and patent publications cited herein are incorporated by reference in their entireties for the teachings relevant to the sentence and/or paragraph in which the citation is presented.
As used herein, “a,” “an” or “the” can mean one or more than one. For example, “a” mutation can mean a single mutation or a multiplicity of mutations.
As used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).
FNR (Fumarate-Nitrate Reductase) is a DNA-binding regulator protein expressed by all enterobacteria including Salmonella spp., Escherichia spp., and Shigella spp. The fnr gene was previously known as oxrA in Salmonella spp. The present inventors have identified FNR as a global regulatory protein for the expression of virulent genes in enterobacteria. An FNR deleted (Δfnr) strain of a known virulent strain of S. enterica serovar Typhimurium was shown to be non-motile, lacking flagella, and having an avirulent phenotype. Thus, the present invention provides FNR deficient (e.g., Δfnr or fnr mutants) strains of enterobacteria that can be used to study the fnr gene, its role in virulence in these organisms, and can further be used as attenuated immunogenic compositions, attenuated vaccines (e.g., live attenuated vaccines) and/or attenuated vaccine vectors.
Enterobacteria are known in the art and are generally pathogens that can infect the gastrointestinal tract of avians and/or mammals. The present invention can be practiced with any suitable enterobacterium in the order Enterobacteriales and optionally in the family Enterobacteriaceae that encodes FNR, including but not limited to bacteria classified in the following genera: Alishewanella, Alterococcus, Aquamonas, Aranicola, Arsenophonus, Azotivirga, Blochmannia, Brenneria, Buchnera, Budvicia, Buttiauxella, Candidatus, Cedecea, Citrobacter, Dickeya, Edwardsiella, Enterobacter, Erwinia (e.g., E. amylovora), Escherichia, Ewingella, Grimontella, Hafnia, Klebsiella (e.g., K. pneumoniae), Kuyvera, Leclercia, Leminorella, Moellerella, Morganella, Obesumbacterium, Pantoea, Pectobacterium, Candidatus Phlomobacter, Photohabdus, Plesiomonas (e.g., P. shigelloides), Pragia, Proteus (e.g., P. vulgaris), Providencia, Rahnella, Raoultella, Salmonella, Samsonia, Serratia (e.g., S. marcenscens), Shigella, Sodalis, Tatumella, Travulsiella, Wigglesworthia, Xenorhabdus, Yersinia (e.g., Y. pestis), and Yokenella.
In particular embodiments, the enterobacterium is a Salmonella spp., an Escherichia spp., or a Shigella spp.
Further, the enterobacterium can optionally be a pathogenic enterobacterium. In particular embodiments, the enterobacterium from which the FNR deficient strain is derived is a pathogenic (e.g., virulent) bacterium as that term is understood in the art, where the attenuating fnr mutation results in a reduction in the pathogenicity. In representative embodiments, the FNR deficient strain is highly attenuated so as to be avirulent (e.g., induces no or insignificant levels of pathogenicity).
The term “pathogenic” is understood in the art, for example, as causing pathogenicity such as morbidity and/or mortality in a subject or population of subjects.
The term “attenuating” with respect to pathogenic microorganisms is understood in the art, for example, as a reduction in pathogenicity (including no detectable pathogenicity) produced in the subject as a result of administration of the FNR deficient enterobacterium strain as compared with the level of pathogenicity produced if an enterobacterium with a fully functional fnr gene (e.g., the wild-type strain) were administered.
Methods of assessing pathogenicity of enterobacteria, and attenuation thereof, are known in the art (e.g., morbidity and/or mortality following challenge in a suitable animal model such as mice or survival in cultured macrophages).
Suitable Salmonella species within the scope of the present invention include but are not limited to S. bongori and S. enterica as well as S. enterica subspecies (e.g., enterica, salamae, arizonae, diarizonae, houtenae and indica). Numerous serovars of S. bongori and S. enterica are known and are within the scope of the present invention. Exemplary S. enterica serovars include Typhimurium, Typhi and Enteritidis.
The present invention can further be practiced with any species of Escherichia including but not limited to E. adecarboxylata, E. albertii, E. blattae, E. coli (including toxigenic strains such as E. coli O157:H7), E. fergusonii, E. hermannii, and E. vulneris.
Suitable species of Shigella include without limitation species in Serogroup A (e.g., S. dysenteriae and serotypes thereof), species in Serogroup B (e.g., S. flexneri and serotypes thereof), species in Serogroup C (e.g., S. boydii and serotypes thereof), and species in Serogroup D (e.g., S. sonnei and serotypes thereof).
The genomic sequences of numerous enterobacteria are known in the art. See, e.g., NCBI Accession No. NC—004337 (Shigella flexneri 2a str. 301); NCBI Accession No. NC—007613 (Shigella boydii Sb227); NCBI Accession No. AP009048 (E. coli W3110); NCBI Accession No. BA000007 (E. coli O157:H7 str. Sakai); NCBI Accession No. AE009952 (Y. pestis KIM); NCBI Accession No. NC—003197 (S. typhimurium LT2); and NCBI Accession No. NC—003198 (S. enterica subsp. enterica serovar Typhi str. CT18).
Likewise, the nucleic acid and amino acid sequences of the fnr gene from various enterobacteria are known in the art.
The attenuated enterobacteria of the present invention comprise an attenuating mutation in the fnr gene. In representative embodiments, the mutation is an attenuating deletion mutation (including truncations) that results in attenuation of the pathogenicity of the bacterium. Other mutations include without limitation attenuating insertions, substitutions and/or frame-shift mutations that result in attenuation of the pathogenicity of the bacterium. In embodiments of the invention, the mutation is a non-polar alteration in the fnr gene.
Deletion and insertion mutations can be any deletion/insertion mutation in the fnr gene that results in attenuation of the pathogenicity of the bacterium. In representative embodiments, the alteration is a deletion or an insertion of at least about 9, 30, 50, 75, 90, 120, 150, 180, 240, 300, 450 or more consecutive nucleotides in the fnr gene that results in attenuation of the pathogenicity of the bacterium. Optionally, essentially all (e.g., at least about 95%, 97%, 98% or more) or all of the fnr coding sequence is deleted. In other embodiments, essentially all or all of the fnr gene, including regulatory elements, is deleted. In particular embodiments, the deletion can extend beyond the fnr gene. Generally, however, the deletion does not render genes essential for growth, multiplication and/or survival non-functional. In particular embodiments, the deletion does not extend into any genes essential for growth, multiplication and/or survival. In embodiments of the invention, the deletion does not extend to genes that are 5′ and/or 3′ of the fnr coding region or the fnr gene.
One FNR deficient strain of S. enterica serovar Typhimurium has been constructed by the inventors and is shown in the Examples.
The FNR deficient enterobacterium strains of the invention can further comprise other mutations, including other attenuating mutations.
Generally, the FNR deficient enterobacterium strains will retain other appropriate genomic sequences to be able to grow, multiply and survive (e.g., in the gut of a host). Thus, the fnr mutations of the invention exclude lethal mutations that unduly inhibit the survival of the organism.
In embodiments of the invention, the FNR mutation results in at least about a 25%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 97%, 98% or more reduction in FNR mRNA, protein and/or activity. Methods of assessing levels of mRNA and proteins levels and FNR activity are known in the art.
The fnr mutation can be combined with any other mutation known in the art, including other attenuating mutations. For example, the fnr mutant enterobacterium can also comprise an arcA mutation. The ArcA protein cooperates with FNR for controlling the transitions from aerobic/anaerobic conditions and vice versa.
The attenuated enterobacteria of the present invention can be used as an attenuated immunogenic compositions or attenuated vaccine against enterobacteria (e.g., a live attenuated vaccine). Enterobacteria are described above. In embodiments of the invention, the enterobacterium is a pathogenic enterobacterium. For example, in particular embodiments, the invention provides live immunogenic compositions or live attenuated vaccines against Salmonella, Shigella or Escherichia. The attenuated enterobacterium vaccine can be used to induce an immune response against one species or against multiple closely related species/genera of enterobacteria (e.g., that cross-react with antibodies produced in response to administration of the attenuated enterobacterium).
Further, the attenuated FNR deficient enterobacterium strains of the invention can be used as vectors, e.g., to deliver an antigen(s) that is heterologous (e.g., foreign) to the enterobacterium vector (including any plasmids carried by the enterobacterium) to induce an immune response against other organisms (e.g., pathogenic organisms). In one embodiment, a heterologous nucleic acid sequence encoding the foreign antigen(s) is incorporated into the genomic DNA of the enterobacterium (e.g., inserted into or in place of a deleted fnr gene). In other embodiments, the heterologous nucleic acid sequence encoding the foreign antigen is incorporated into a plasmid that is carried by an attenuated FNR deficient host (e.g., a Δfnr host). Plasmids that are compatible with the various enterobacteria are known in the art.
The attenuated FNR deficient strains can further be used as vectors to deliver therapeutic proteins and untranslated RNAs (e.g., siRNA, shRNA, antisense RNA).
Methods of expressing foreign antigens in enterobacteria are known to those skilled in the art. For example, the foreign antigen can be expressed as part of a fusion with one of the structural proteins of the bacterial host (e.g., expressed on the surface of the bacterium) such as a flagellin protein (see, e.g., Chauhan et al., (2005) Molecular and Cellular Biochemistry 276:1-6) or a membrane protein as known in the art. See also, Chinchilla et al., (2007) Infection Immun. 75: 3769. In other embodiments, the foreign antigen is not expressed as a fusion with a host structural protein. According to this embodiment, the heterologous nucleic acid encoding the foreign antigen can optionally be operably associated with a leader sequence directing secretion of the foreign antigen from the bacterial cell.
The heterologous nucleic acid sequence encoding the foreign antigen can be operatively associated with any suitable promoter or other regulatory sequence. The promoter or regulatory sequence can be native or foreign to the host, can be native or foreign to the heterologous nucleic acid, and can further be partially or completely synthetic.
The codon usage of the heterologous nucleic acid sequence can be optimized for expression in the enterobacterium using methods known to those skilled in the art (see, e.g., Chinchilla et al., (2007) Infection Immun. 75: 3769.
The foreign antigen can be any suitable antigen known in the art, and can further be from a bacterial, yeast, fungal, protozoan or viral source. Suitable antigens include, but are not limited to antigens from pathogenic infectious agents.
The antigen can be an antigen from a pathogenic microorganism, which includes but is not limited to, Rickettsia, Chlamydia, Mycobacteria, Clostridia, Corynebacteria, Mycoplasma, Ureaplasma, Legionella, Shigella, Salmonella, pathogenic Escherichia coli species, Bordatella, Neisseria, Treponema, Bacillus, Haemophilus, Moraxella, Vibrio, Staphylococcus spp., Streptococcus spp., Campylobacter spp., Borrelia spp., Leptospira spp., Erlichia spp., Klebsiella spp., Pseudomonas spp., Helicobacter spp., and any other pathogenic microorganism now known or later identified (see, e.g., Microbiology, Davis et al, Eds., 4th ed., Lippincott, New York, 1990, the entire contents of which are incorporated herein by reference for the teachings of pathogenic microorganisms).
Specific examples of microorganisms from which the antigen can be obtained include, but are not limited to, Helicobacter pylori, Chlamydia pneumoniae, Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma pneumoniae, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus viridans, Enterococcus faecalis, Neisseria meningitidis, Neisseria gonorrhoeae, Treponema pallidum, Bacillus anthracis, Salmonella typhi, Vibrio cholera, Pasteurella pestis, Pseudomonas aeruginosa, Campylobacter jejuni, Clostridium difficile, Clostridium tetani, Clostridium botulinum, Mycobacterium tuberculosis, Borrelia burgdorferi, Haemophilus ducreyi, Corynebacterium diphtheria, Bordetella pertussis, Bordetella parapertussis, Bordetella bronchiseptica, Haemophilus influenza, and enterotoxic Escherichia coli.
The antigen can further be an antigen from a pathogenic protozoa, including, but not limited to, Plasmodium spp. (e.g., malaria antigens), Babeosis spp., Schistosoma spp., Trypanosoma spp., Pneumocystis carnii, Toxoplasma spp., Leishmania spp., and any other protozoan pathogen now known or later identified.
The antigen can also be an antigen from pathogenic yeast and fungi, including, but not limited to, Aspergillus spp., Candida spp., Cryptococcus spp., Histoplasma spp., Coccidioides spp., and any other pathogenic fungus now known or later identified.
Suitable antigens can include, but are not limited to, viral antigens such as antigens including but not limited to human hepatitis C virus (HCV) antigens and influenza antigens.
Other specific examples of various antigens include, but are not limited to, the B1 protein of hepatitis C virus (Bruna-Romero et al. (1997) Hepatology 25: 470-477), amino acids 252-260 of the circumsporozoite protein of Plasmodium berghei [Allsopp et al. (1996) Eur. J. Immunol. 26: 1951-1958], the influenza A virus nucleoprotein [e.g., residues 366-374; Nomura et al. (1996) J. Immunol. Methods 193: 4149], the listeriolysin O protein of Listeria monocytogenes [residues 91-99; An et al. (1996) Infect. Immun. 64: 1685-1693 ], P. falciparum antigens (causing malaria, e.g., tCSP), hepatitis B surface antigen [Gilbert et al. (1997) Nature Biotech. 15: 1280-1283], and E coli O157.H1.
The term “antigen” as used herein includes toxins such as the neurotoxin tetanospasmin produced by Clostridium tetani and the toxin produced by E. coli O157:H7.
In particular embodiments, the attenuated enterobacteria of the invention express a foreign antigen(s) and can be used to induce an immune response against both the enterobacterium and the organism(s) from which the foreign antigen(s) is derived and, optionally, other species/genera closely related to either of the foregoing (e.g., that cross-react with antibodies produced in response to administration of the attenuated enterobacterium).
There is no particular size limitation to the heterologous nucleic acid encoding the foreign antigen. When incorporated into the genomic DNA, the heterologous nucleic acid will generally be at least about 30, 50, 75, 100, 150 or 200 nucleotides in length and/or less than about 1, 1.5, 2, 2.5 or 3 kilobases in length. When carried by a plasmid, the heterologous nucleic acid can generally be longer, e.g., at least about 30, 50, 75, 100, 150, 200, 500 or 1000 nucleotides in length and/or less than about 5, 10, 12, 14, 16, 18 or 20 kilobases in length.
In representative embodiments, the FNR deficient enterobacterium is a Δfnr mutant, which advantageously reduces the probability of reversion to the wild-type pathogenic phenotype. For example, most current live attenuated vaccine strains against typhoid are auxotrophs for some nutrients, which are likely less stable than the deletion mutants.
The present invention can be used for therapeutic/prophylactic and non-therapeutic/prophylactic purposes. For example, the present invention provides FNR deficient (e.g., Δfnr) enterobacteria strains that can be used to study the fnr gene, its role in virulence in these organisms, and as attenuated immunogenic compositions, attenuated vaccines (e.g., live attenuated vaccines) and attenuated vaccine vectors (e.g., live attenuated vaccine vectors).
With respect to uses as an attenuated vaccine or vaccine vector, the present invention finds use in both veterinary and medical applications. Suitable subjects include avians, mammals and fish, with mammals being preferred. The term “avian” as used herein includes, but is not limited to, chickens, ducks, geese, quail, turkeys and pheasants. The term “mammal” as used herein includes, but is not limited to, primates (e.g., simians and humans), bovines, ovines, caprines, porcines, equines, felines, canines, lagomorphs, rodents (e.g., rats and mice), etc. Human subjects include fetal, neonatal, infant, juvenile and adult subjects.
The invention can be used in a therapeutic and/or prophylactic manner. For example, in one embodiment, to protect against an infectious disease, subjects may be vaccinated prior to exposure, e.g., as neonates or adolescents. Adults that have not previously been exposed to the disease may also be vaccinated.
In particular embodiments, the present invention provides a pharmaceutical composition comprising a FNR deficient (e.g., Δfnr) strain enterobacterium (optionally, a live FNR deficient enterobacterium) in a pharmaceutically-acceptable carrier, which can also include other medicinal agents, pharmaceutical agents, carriers, adjuvants, diluents, etc. For injection, the carrier is typically a liquid. For other methods of administration, the carrier may be either solid or liquid, such as sterile, pyrogen-free water or sterile pyrogen-free phosphate-buffered saline solution. For inhalation administration, the carrier will be respirable, and is optionally in solid or liquid particulate form. Formulation of pharmaceutical compositions is well known in the pharmaceutical arts [see, e.g., Remington's Pharmaceutical Sciences, 15th Edition, Mack Publishing Company, Easton, Pa. (1975)].
By “pharmaceutically acceptable” it is meant a material that is not biologically or otherwise undesirable, e.g., the material may be administered to a subject without causing undesirable biological effects.
The FNR deficient strains of the invention can be administered to elicit an immune response. Typically, immunological compositions of the present invention comprise an immunogenically effective amount of the FNR deficient strain enterobacterium as disclosed herein, optionally in combination with a pharmaceutically acceptable carrier.
An “immunogenically effective amount” is an amount that is sufficient to induce an immune response in the subject to which the composition is administered. Nonlimiting examples of dosages include about 104 to 109 colony forming units (cfu), about 105 to 108 cfu or about 106 to 107 cfu. Optionally, one or more booster dosages (e.g., about 103 to 108 cfu or 104 to 105 cfu) can be administered.
The invention also encompasses methods of producing an immune response in a subject, the method comprising: administering a FNR deficient (e.g., Δfnr) enterobacterium strain of the invention or a pharmaceutical formulation containing the same to a subject in an immunogenically effective amount so that an immune response is produced in the subject.
The terms “vaccination” or “immunization” are well-understood in the art. For example, the terms vaccination or immunization can be understood to be a process that increases a subject's immune reaction to antigen and thereby enhance the ability to resist and/or overcome infection.
Any suitable method of producing an immune response (e.g., immunization) known in the art can be employed in carrying out the present invention, as long as an active immune response (preferably, a protective immune response) is elicited.
In representative embodiments, less pathogenicity (including no detectable pathogenicity) is produced in the subject as a result of administration of the FNR deficient enterobacterium strain as compared with pathogenicity produced if an enterobacterium with a fully functional fnr gene (e.g., the wild-type strain) were administered (e.g., at least about a 25%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 97%, 98% or more reduction in pathogenicity).
Vaccines can be given as a single dose schedule or in a multiple dose schedule. A multiple dose schedule is one in which a primary course of administration may consist of about 1 to 10 separate doses, followed by other doses (i.e., booster doses) given at subsequent time intervals to maintain and/or reinforce the immune response, for example, at about 1 to 4 months for a second dose, and if needed, a subsequent dose(s) after another several months or year. The dosage regimen will also, at least in part, be determined by the need of the individual and be dependent upon the judgment of the medical or veterinary practitioner.
An “active immune response” or “active immunity” is characterized by “participation of host tissues and cells after an encounter with the immunogen. It involves differentiation and proliferation of immunocompetent cells in lymphoreticular tissues, which lead to synthesis of antibody or the development of cell-mediated reactivity, or both.” Herbert B. Herscowitz, Immunophysiology: Cell Function and Cellular Interactions in Antibody Formation, in
A “protective” immune response or “protective” immunity as used herein indicates that the immune response confers some benefit to the subject in that it prevents or reduces the incidence of disease, the progression of the disease and/or the symptoms of the disease. Alternatively, a protective immune response or protective immunity may be useful in the treatment of disease including infectious disease. The protective effects may be complete or partial, as long as the benefits of the treatment outweigh any disadvantages thereof.
Administration of the attenuated enterobacteria and compositions of the invention can be by any means known in the art, including oral, rectal, topical, buccal (e.g., sub-lingual), vaginal, intra-ocular, parenteral (e.g., subcutaneous, intramuscular including skeletal muscle, cardiac muscle, diaphragm muscle and smooth muscle, intradermal, intravenous, intraperitoneal), topical (e.g., mucosal surfaces including airway surfaces), intranasal, transmucosal, intratracheal, transdermal, intraventricular, intraarticular, intrathecal and inhalation administration.
The most suitable route in any given case will depend on the nature and severity of the condition being treated, the FNR deficient strain enterobacterium, and the composition being administered.
The FNR deficient enterobacterium strain can be formulated for administration in a pharmaceutical carrier in accordance with known techniques. See, e.g., Remington, The Science and Practice of Pharmacy (9th Ed. 1995). In the manufacture of a pharmaceutical formulation according to the invention, the FNR deficient enterobacterium strain is typically admixed with, inter alia, an acceptable carrier. The carrier can be a solid or a liquid, or both, and is optionally formulated as a unit-dose formulation, which can be prepared by any of the well-known techniques of pharmacy.
For injection, the carrier is typically a liquid, such as sterile pyrogen-free water, pyrogen-free phosphate-buffered saline solution, bacteriostatic water, or Cremophor EL[R] (BASF, Parsippany, N.J.). For other methods of administration, the carrier can be either solid or liquid.
For oral administration, the FNR deficient enterobacterium strain can be administered in solid dosage forms, such as capsules, tablets, and powders, or in liquid dosage forms, such as elixirs, syrups, and suspensions. The FNR deficient strain enterobacterium can be encapsulated in gelatin capsules together with inactive ingredients and powdered carriers, such as glucose, lactose, sucrose, mannitol, starch, cellulose or cellulose derivatives, magnesium stearate, stearic acid, sodium saccharin, talcum, magnesium carbonate and the like. Examples of additional inactive ingredients that can be added to provide desirable color, taste, stability, buffering capacity, dispersion or other known desirable features are red iron oxide, silica gel, sodium lauryl sulfate, titanium dioxide, edible white ink and the like. Similar diluents can be used to make compressed tablets. Both tablets and capsules can be manufactured as sustained release products to provide for continuous release of medication over a period of hours. Compressed tablets can be sugar coated or film coated to mask any unpleasant taste and protect the tablet from the atmosphere, or enteric-coated for selective disintegration in the gastrointestinal tract. Liquid dosage forms for oral administration can contain coloring and flavoring to increase patient acceptance.
Formulations suitable for buccal (sub-lingual) administration include lozenges comprising the FNR deficient enterobacterium strain in a flavored base, usually sucrose and acacia or tragacanth; and pastilles comprising the FNR deficient enterobacterium strain in an inert base such as gelatin and glycerin or sucrose and acacia.
Formulations of the present invention suitable for parenteral administration can comprise sterile aqueous and non-aqueous injection solutions of the FNR deficient enterobacterium strain, which preparations are generally isotonic with the blood of the intended recipient. These preparations can contain anti-oxidants, buffers, bacteriostats and solutes, which render the formulation isotonic with the blood of the intended recipient. Aqueous and non-aqueous sterile suspensions can include suspending agents and thickening agents. The formulations can be presented in unit\dose or multi-dose containers, for example sealed ampoules and vials, and can be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example, saline or water-for-injection immediately prior to use.
Extemporaneous injection solutions and suspensions can be prepared from sterile powders, granules and tablets. For example, in one aspect of the present invention, there is provided an injectable, stable, sterile composition comprising a FNR deficient enterobacterium strain of the invention, in a unit dosage form in a sealed container. Optionally, the composition is provided in the form of a lyophilizate, which is capable of being reconstituted with a suitable pharmaceutically acceptable carrier to form a liquid composition suitable for injection thereof into a subject.
Formulations suitable for rectal or vaginal administration can be presented as suppositories. These can be prepared by admixing the FNR deficient enterobacterium strain with one or more conventional excipients or carriers, for example, cocoa butter, polyethylene glycol or a suppository wax, which are solid at room temperature, but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the FNR deficient FNR deficient enterobacterium strain.
Formulations suitable for topical application to the skin can take the form of an ointment, cream, lotion, paste, gel, spray, aerosol, or oil. Carriers that can be used include petroleum jelly, lanoline, polyethylene glycols, alcohols, transdermal enhancers, and combinations of two or more thereof.
Formulations suitable for transdermal administration can be presented as discrete patches adapted to remain in intimate contact with the epidermis of the recipient for a prolonged period of time. Formulations suitable for transdermal administration can also be delivered by iontophoresis [see, for example, Pharmaceutical Research 3 (6):318 (1986)] and typically take the form of an optionally buffered aqueous solution. Suitable formulations comprise citrate or bis\tris buffer (pH 6) or ethanol/water.
The FNR deficient enterobacterium strain can be formulated for nasal administration or otherwise administered to the lungs of a subject by any suitable means, for example, by an aerosol suspension of respirable particles comprising the FNR deficient enterobacterium strain, which the subject inhales. The respirable particles can be liquid or solid. The term “aerosol” includes any gas-borne suspended phase, which is capable of being inhaled into the bronchioles or nasal passages. Specifically, an aerosol includes a gas-borne suspension of droplets, as can be produced in a metered dose inhaler or nebulizer, or in a mist sprayer. An aerosol also includes a dry powder composition suspended in air or other carrier gas, which can be delivered by insufflation from an inhaler device, for example. See Ganderton & Jones, Drug Delivery to the Respiratory Tract, Ellis Horwood (1987); Gonda (1990) Critical Reviews in Therapeutic Drug Carrier Systems 6:273-313; and Raeburn et al. (1992) J. Pharmacol. Toxicol. Methods 27:143-159. Aerosols of liquid particles can be produced by any suitable means, such as with a pressure-driven aerosol nebulizer or an ultrasonic nebulizer, as is known to those of skill in the art. See, e.g., U.S. Pat. No. 4,501,729. Aerosols of solid particles comprising the FNR deficient enterobacterium strain can likewise be produced with any solid particulate medicament aerosol generator, by techniques known in the pharmaceutical art.
In particular embodiments of the invention, administration is by subcutaneous or intradermal administration. Subcutaneous and intradermal administration can be by any method known in the art, including but not limited to injection, gene gun, powderject device, bioject device, microenhancer array, microneedles, and scarification (i.e., abrading the surface and then applying a solution comprising the FNR deficient enterobacterium strain).
In other embodiments, the FNR deficient enterobacterium strain is administered intramuscularly, for example, by intramuscular injection.
The examples which follow are set forth to illustrate the present invention, and are not to be construed as limiting thereof.
EXAMPLE 1 Materials and Methods Bacterial strains. Wild-type (WT) serovar Typhimurium (ATCC 14028s) and its isogenic fnr mutant (NC 983) were used throughout the studies described herein. The mutant strain was constructed by transducing the fnr::Tn10 mutation from serovar Typhimurium [SL2986/TN 2958 (fnr::Tn10)] to strain 14028s using P22 phage (all from the culture collection of S. Libby). The transductants were plated on Evans blueuranine agar, and the tetracycline marker was eliminated (Bochner et al., (1980) J. Bacteriol. 143:926-933). The Tets and FNR− phenotypes were confirmed by the inability of NC983 (fnr mutant) to grow on media containing tetracycline (10 μg/ml) and by its inability to grow anaerobically on M9 minimal medium containing glycerol plus nitrate, respectively. Sequence analysis of fnr and neighboring genes (i.e., ogt and ydaA, respectively) in NC 893 showed that the remnant of Tn10 (tnpA) interrupts fnr between bp 106 and 107 and has no polar effect on ogt or ydaA (
For complementation studies, a low-copy-number plasmid expressing fnr (pfnr) was constructed. The complete fnr sequence starting from the stop codon of ogtA (TGA [indicated in boldface type]) to 21 bp downstream of fnr (i.e., a 972 bp fragment) was amplified from WT strain 14028s with the following primers: fnr-Forward, 5′-ATATCCATGGTGAATATACAGGAAAAAGTGC-3′ (an NcoI site is underlined; SEQ ID NO:1); fnr-Reverse, 5′-ATATATTCAGCTGCATCAATGGTTTAGCTGACG-3′ (a PvuII site is underlined; SEQ ID NO:2). The PCR product was digested with Ncol and PvuII and ligated into the low-copy-number vector pACYC184 cut with NcoI and PvuII. Thus, in the new plasmid (pfnr) the Cmr gene in pACYC184 is replaced with the fnr gene. The plasmid (pfnr) was electroporated and maintained in E. coli DH5α. Transformants were confirmed for Tetr (15 μg/ml) and Cms (20 μg/ml) on Luria-Bertani (LB) plates, and the presence of the fnr gene was confirmed by restriction analysis using EcoRI and HindIII. The plasmid isolated from DH5α was used to complement the fnr mutant. Transformants were selected on LB plates containing tetracycline (15 μg/ml).
Growth conditions. The WT and the fnr mutant were grown anaerobically at 37° C. in MOPS (morpholinepropanesulfonic acid)-buffered (100 mM, pH 7.4) LB broth supplemented with 20 mM D-xylose (LB-MOPS-X). This medium was used in order to avoid the indirect effects of pH and catabolite repression. A Coy anaerobic chamber (Coy, Ann Arbor, Mich.) and anaerobic gas mixture (10% H2, 5% CO2, and 85% N2) were used. All solutions were preequilibrated for 48 h in the chamber. Cells from frozen stocks were used to inoculate LB-MOPS-X broth. Cultures were grown for 16 h and used to inoculate fresh anoxic media. The anaerobic growth kinetics of the mutant and the WT strains were similar, and the doubling times of the fnr mutant and the WT were 53.9±1.2 and 45.4±2.9 min, respectively.
RNA isolation. Anaerobic cultures were used to inoculate three independent flasks each containing 150 ml of anoxic LB-MOPS-X. The three independent cultures were grown to an optical density at 600 nm (OD600) of 0.25 to 0.35, pooled, and treated with RNAlater (QIAGEN, Valencia, Calif.) to fix the cells and preserve the quality of the RNA. Total RNA was extracted with the Rneasy RNA extraction kit (QIAGEN), and the samples were treated with RNase-free DNase (Invitrogen, Carlsbad, Calif.). The absence of contaminating DNA and the quality of the RNA was confirmed by PCR amplification of known genes and by using agarose gel electrophoresis. Aliquots of the RNA samples were kept at −80° C. for use in the microarray and quantitative real-time reverse transcription-PCR (qRT-PCR) studies.
Microarray studies. Serovar Typhimurium microarray slides were prepared and used as previously described in Porwollik, S. et al., “The delta uvrB mutations in the Ames strains of Salmonella span 15-119 gene” Mutat. Res. 483:1-11 (2001). The SuperScript Indirect cDNA labeling system (Invitrogen) was used to synthesize the cDNA for the hybridizations. Each experiment consisted of two hybridizations, on two slides, and was carried out in Corning Hybridization Chambers at 42° C. overnight. Dye swapping was performed to avoid dye-associated effects on cDNA synthesis. The slides were washed at increasing stringencies (2×SSC [1×SSC is 0.15 M NaCl plus 0.015 M sodium citrate], 0.1% sodium dodecyl sulfate [SDS], 42° C.; 0.1% SSC, 0.1% SDS, room temperature; 0.1% SSC, room temperature). Following hybridization, the microarrays were scanned for the Cy3 and Cy5 fluorescent signals with a ScanArray 4000 microarray scanner from GSI Lumonics (Watertown, Mass.). The intensity of every spot was codified as the sum of the intensities of all the pixels within a circle positioned over the spot itself and the background as the sum of the intensities of an identical number of pixels in the immediate surroundings of the circled spot.
Data analysis. Cy3 and Cy5 values for each spot were normalized over the total intensity for each dye to account for differences in total intensity between the two scanned images. The consistency of the data obtained from the microarray analysis was evaluated by two methods: (i) a pair-wise comparison, calculated with a two-tailed Student's t test and analyzed by the MEAN and TTEST procedures of SAS-STAT statistical software (SAS Institute, Cary, N.C.) (the effective degrees of freedom for the t test were calculated as described previously in Satterthwaite, F. E. “An approximate distribution of estimates of variance components” Biometrics Bull. 2:110-114 (1946)); and (ii) a regularized t test followed by a posterior probability of differential expression [PPDE (p)] method. These statistical analyses are implemented in the Cyber-T software package available online at the website of the Institute for Genomics and Bioinformatics of the University of California, Irvine. The signal intensity at each spot from the FNR mutant and the WT were background subtracted, normalized, and used to calculate the ratio of gene expression between the two strains. All replicas were combined, and the median expression ratios and standard deviations were calculated for open reading frames (ORFs) showing ≧2.5-fold change.
qRT-PCR. qRT-PCR was used to validate the microarray data, where 19 genes were randomly chosen from the differentially expressed genes. This technique was also used to confirm the expression of a set of selected genes. qRT-PCRs were carried out with the QuantiTect SYBR green RT-PCR kit (QIAGEN) and an iCycler (Bio-Rad, Hercules, Calif.), and the data were analyzed by the Bio-Rad Optical System software, version 3.1, according to manufacturer specifications. To ensure accurate quantification of the mRNA levels, three amplifications for each gene were made with 1:5:25 dilutions of the total RNA. Measured mRNA levels were normalized to the mRNA levels of the housekeeping gene rpoD (σ70). Normalized values were used to calculate the ratios of the expression levels in the fnr mutant relative to the WT.
Logo graph and promoter analysis. The information matrix for the generation of the FNR logo was produced by using the alignment of the E. coli FNR binding sequences, available at http://arep.med.harvard.edu/ecoli_matrices/. The alignment of the FNR motifs from this website did not include the motifs present in the sodA and mutM promoters; therefore, they were included in our analysis. To account for differences in nucleotide usage or slight variations in consensus sequences, a second alignment was built for serovar Typhimurium using the 5′ regions of the homologous genes originally used to build the E. coli information matrix. The alignment was used to prepare a new information matrix using the Patser software (version 3d), available at http://rsat.ub.ac.be/rsat/. A graphical representation (
Motility assay and electron microscopy. The motilities of the WT, the fnr mutant, and the complemented mutant/pfnr were evaluated under anoxic conditions. Ten microliters of anaerobically grown (16 h) cells were spotted onto LB-MOPS-X agar (0.6% agar) plates and incubated at 37° C. for 24 h. The diameter of the growth halo was used as a measure of motility. Scanning electron microscopy (SEM) was used to examine the morphology of the extracellular surfaces. WT and fnr cultures were grown anaerobically (OD600, 0.3 to 0.4) and centrifuged, and the pellets were resuspended in a fixative solution (3% glutaraldehyde in 0.1 M phosphate-buffered saline [PBS] [pH 7.4]) under anaerobic conditions. The fixed samples were rinsed in 0.1 M PBS buffer, postfixed with 1% osmium tetroxide in 0.1 M PBS for 2 h, and rinsed with PBS, all at 4° C. An aliquot of each sample was filtered through a 0.1-μm filter. Each filter was dehydrated through a graded ethanol series (up to 100%), brought to room temperature, critical point dried with liquid CO2 (Tousimis Research, Rockville, Md.), placed on stubs, and sputter coated with Au/Pd (Anatech Ltd., Denver, N.C.). Samples were viewed at 15 kV with a JEOL 5900LV SEM (JEOL USA, Peabody, Mass.). Transmission electron microscopy (TEM) and negative staining were used to visualize the flagella. WT and fnr cultures were grown anaerobically (OD600, 0.3 to 0.4), and a 20-μl aliquot of each sample was separately placed on a Formvar-carbon grid. The grids were washed with 0.1 M sodium acetate (pH 6.6), negatively stained with 2% phosphotungstic acid (PTA), and air dried for 5 min before being viewed at 80 kV with a JEOL JEM-100S TEM (JEOL USA, Peabody, Mass.).
Pathocenicity assays. Immunocompetent 6- to 8-week-old C57BL/6 mice and their congenic iNOS−/− and pg91phox−/− immunodeficient mice (bred in the University of Colorado Health Science Center [UCHSC] animal facility according to Institutional Animal Care and Use Committee guidelines) were used in this study. Stationary-phase serovar Typhimurium (WT and fnr mutant) cultures grown aerobically in LB-MOPS-X broth were used, and the cells were diluted in PBS. For oral (p.o.) challenge, groups of 10 mice were gavaged with 5×106 or 5×107 CFU in 200 μl of PBS/mouse. For intraperitoneal (i.p.) challenge, groups of five mice were inoculated with 250 CFU in 500 μl of PBS/mouse. Mortality was scored over a 15- to 30-day period.
Macrophage assay. Peritoneal macrophages were harvested from C57BL/6 mice and pg91phox−/− immunodeficient mice (bred in the UCHSC animal facility) 4 days after intraperitoneal inoculation with 1 mg/ml sodium periodate and used as previously described in DeGroote, M. A. et al. “Periplasmic superoxide dismutase protects Salmonella from products of phagocyte NADPH-oxidase and nitric oxide synthase” Proc. Natl. Acad. Sci. 94:13997-14001 (1997). Macrophages were challenged (multiplicity of infection of 2) for 25 min with the different test strains. Stationary-phase cultures grown aerobically in LB-MOPS-X broth were used as outlined above. Prior to infection, each strain was opsonized with 10% normal mouse serum for 20 min. After the challenge, extracellular bacteria were removed from the monolayers by washing with prewarmed RPMI medium (Cellgro, Herndon, Va.) containing gentamicin (6 mg/ml) (Sigma), the Salmonella-infected macrophages were lysed at indicated time points, and the surviving bacteria were enumerated on LB agar plates. The results are expressed as percent survival relative to the number of viable intracellular bacteria recovered at time zero (i.e., after washing and removal of the extracellular bacteria, 25 min after infection).
Microarray data. The microarray data are accessible via GEO accession number GSE3657 at http://www.ncbi.nlm.nih.gov/qeo (the disclosure of which is incorporated herein by reference in its entirety).
EXAMPLE 2 Transcriptome ProfilingOut of 4,579 genes, the two-tailed Student t test produced a set of 1,664 coding sequences showing significant differences (P<0.05) between the fnr mutant and the WT. The analysis was restricted to include highly affected genes (i.e., having a ratio of ≧2.5-fold). Under this constraint, 311 genes were differentially expressed in the fnr mutant relative to the WT; of these, 189 genes were up-regulated and 122 genes were down-regulated by FNR (Table 3). The 311 FNR-regulated genes were classified into clusters of orthologous groups (COGs) as defined at http://www.ncbi.nlm.nih.gov/COG. Throughout the study levels of transcription in the fnr mutant were compared to that in the WT strain. Thus, genes repressed by FNR possess values of >1, while genes activated by FNR have values of <1.
In order to globally validate the microarray data, 19 of the 311 differentially expressed genes for qRT-PCR were selected. The measured levels of mRNA were normalized to the mRNA levels of the housekeeping gene rpoD. The specific priers used for qRT-PCR and the normalized mRNA levels are shown in Table 1. The microarray and qRT-PCR data were log2 transformed and plotted (
To determine whether a binding site for FNR might be present in the region upstream of the candidate FNR-regulated genes, 5′ regions of these genes were searched for the presence of a putative FNR-binding motif using a Salmonella logo graph (
Transcription of the genes required for aerobic metabolism, energy generation, and nitric oxide detoxification was repressed by FNR. In particular, the genes coding for cytochrome c oxidase (cyoABCDE), cytochrome cd complex (cydAB), NADH-dehydrogenase (nuoBCEFJLN), succinyl-coenzyme A (CoA) metabolism (sucBCD), fumarases (fumB, stm0761, and stm0762), and the NO.-detoxifying flavohemoglobin (hmpA) were expressed at higher levels in the fnr mutant than in the WT (Table 3). Also, genes required for L-lactate metabolism (IId-PRD) and for the production of phosphoenolpyruvate (pykF), oxaloacetate (ppc), and acetoacetyl-CoA (yqeF) were expressed at higher levels in the mutant than in the WT (Table 3).
EXAMPLE 4 FNR as an ActivatorSeveral genes associated with anaerobic metabolism, flagellar biosynthesis, motility, chemotaxis, and Salmonella pathogenesis were activated by FNR. The genes constituting the dms operon, dmsABC (encoding the anaerobic dimethyl sulfoxide reductase), required for the use of dimethyl sulfoxide (DMSO) as an anaerobic electron acceptor, had the lowest expression levels (i.e., −200-, −62-, and −23-fold, respectively) in the fnr mutant relative to the WT (Table 3). Two other operons coding for putative anaerobic DMSO reductases (STM4305 to STM4307 and STM2528 to STM2530) were also under positive control by FNR. The genes required for the conversion of pyruvate to phosphoenolpyruvate (pps), Ac-CoA (aceF), Ac-P (pta), and OAc (ackA), as well as those for the production of formate (tdcE, yfiD, focA) and D-lactate (IdhA), were expressed at lower levels in the fnr mutant than in the WT. In addition, the genes coding for a universal stress protein (ynaF), a ferritinlike protein (ftnB), an ATP-dependent helicase (hrpA), and aerotaxis/redox sensing (aer) were also positively regulated by FNR (Table 3).
The genes for ethanolamine utilization (eut operon) had lower transcript levels in the fnr mutant (
Several of the middle flagellar (class 2) genes (e.g., flgNMDEFGKL and fliZADSTHJLM) and late flagellar (class 3) genes (e.g., cheZYBRMWA, motBA, aer, trg, and tsr) had lower transcript levels in the fnr mutant than in the WT (
Several genes in SPI-1 (e.g., prgKJIH, iagB, sicA, spaPO, invJICBAEGF) had lower levels of expression in the fnr mutant than in the WT (
Expression of the flagellar biosynthesis, motility, and chemotaxis genes was lower in the fnr mutant than in the WT. Therefore, the WT, fnr mutant was compared to the mutant cells harboring pfnr for motility in soft agar under anaerobic conditions. The data indicate that the fnr mutant was nonmotile and that the lack of motility was complemented (˜75%) by the inclusion of pfnr. The 100% complementation by pfnr is probably due to extra copies of the global regulator FNR. The WT was also compared to the mutant for the presence of flagella by SEM and TEM. Taken together, these data show that the fnr mutant is nonmotile due to the lack of flagella.
EXAMPLE 6 Effects of FNR on Pathogenicity and Killing by Macrophages FNR positively regulates the expression of various loci (see Table 3), such as motility and SPI-1 genes that are important determinants for Salmonella pathogenesis, so the virulence of fnr in a murine model of mucosal and acute infection was tested. In immunocompetent C57BL/6 mice, the fnr mutant was completely attenuated over a 15-day period following an oral challenge with 5×106 or 5×107 CFU/mouse, while the WT strain killed all mice within 10 or 12 days, respectively (
The foregoing is illustrative of the present invention, and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein.
aSTM3211 (rpoD) was used as the reference gene where no significant change in expression level was observed. The primer sequences (5′ to 3′) used for rpoD were as follows: CGATGTCTCTGAAGAAGTGC (forward; SEQ ID NO:41) and TTCAACCATCTCTTTCTTCG (reverse; SEQ ID NO:42). The size of the fragment generated is 150 bp.
bLocation of the open reading frame (ORF) in the S. Typhimurium LT2 genome.
cRespective gene name or symbol.
dFor each set, the first primer is the forward primer and the second primer is the reverse primer.
eSize of the amplified PCR product.
fFunctional classification according to the KEGG (Kyoto Encyclopedia of Genes and Genomes) database.
gExpression levels of quantitative reverse transcriptase polymerase chain reaction - values shown as the ratio between the fnr mutant and the wild-type; where values <1 indicate that FNR acts as an activator, and values >1 indicate FNR acts as a repressor.
hExpression levels from the microarray data - values shown as the ratio between the fnr mutant and the wild-type; where values <1 indicate that FNR acts as an activator, and values >1 indicate FNR acts as a repressor.
iExpression levels of quantitative reverse transcriptase polymerase chain reaction comparing the fnr mutant versus the wild-type - shown in signal to log2 ratio (SLR).
jExpression levels of microarray data comparing the fnr mutant versus the wild-type - shown in signal to 10g2 ratio (SLR).
adSTM3211 (rpoD) was used as the reference gene where no significant change in expression level was observed. The primer sequences used for rpoD were as follows: 5′-CGATGTCTCTGAAGAAGTGC-3′ (forward; SEQ ID NO:41) and 5′-TTCAACCATCTCTTTCTTCG-3′ (reverse; SEQ ID NO:42). The size of the fragment generated was 150 bp.
bLocation of the open reading frame (ORF) in the S. Typhimurium LT2 genome.
cRespective gene name or symbol.
dFor each set, the first primer is the forward and the second primer is the reverse.
eSize of the amplified PCR product.
fRatio of the transcription levels in the fnr mutant relative to the wild-type.
aLocation of the open reading frame (ORF) in the S. Typhimurium LT2 genome.
bFunctional category assigned to the gene by the National Center for Biotechnology Information, Cluster of Orthologous Genes (COGs). The designations of functional categories are as follows: C, energy production and conversion, D, cell cycle control and mitosis, E, amino acid metabolism and transport, F, nucleotide metabolism and transport, G, carbohydrate metabolism and transport, H, coenzyme metabolism and transport, I, lipid metabolism and transport, J, translation, K, transcription, L,
cRespective gene name or symbol.
dFunctional classification according to the KEGG (Kyoto Encyclopedia of Genes and Genomes) database.
eThe numerical value of t for the t test (statistical method).
fThe degrees of freedom employed for the analysis of each gene.
gThe probability associated with the t test for each gene.
hRatio between the expression level of the fnr mutant relative to the wild-type.
iThe strand on which the motif has been localized. R, reverse; D, direct; NA, not available in the Regulatory Sequence Analysis Tools (RSAT) database (the locus identity was not recognized), and a blank cell indicates that no motif was present.
jThe starting position of the putative motif. The positions are relative to the region searched and span from −300 to +50 relative to the starting ATG.
kThe ending position of the putative motif. The positions are relative to the region searched and span from −300 to +50 relative to the starting ATG.
lThe sequence of the HIGHEST RANKING putative motif (capitalized letters) and 4 base pairs (bps) flanking either side of the region (lower case letters). A blank cell indicates that no motif was present. All of the sequences are reported from the 5′ to the 3′ end of the ORF (Open Reading Frame) analyzed.
mThe score indicating the similarity of the motif to the information matrix. The cutoff used was a score higher than 4.00 or a In(P) lower than −6.5.
nThe natural logarithm of the probability that the putative motif is randomly similar to the information matrix. The cutoff used was a score higher than 4.00 or a In(P) lower than −6.5.
Claims
1. A pharmaceutical composition comprising an attenuated enterobacterium comprising an attenuating mutation in the fnr gene in a pharmaceutically acceptable carrier.
2. The pharmaceutical composition of claim 1, wherein the attenuating mutation is an attenuating deletion mutation.
3. The pharmaceutical composition of claim 1, wherein the attenuated enterobacterium is an attenuated Salmonella.
4. The pharmaceutical composition of claim 3, wherein the attenuated Salmonella is an attenuated S. enterica serovar Typhimurium.
5. The pharmaceutical composition of claim 1, wherein the attenuated enterobacterium is an attenuated Shigella.
6. The pharmaceutical composition of claim 1, wherein the attenuated enterobacterium is an attenuated Escherichia coli.
7. The pharmaceutical composition of claim 6, wherein the attenuated E. coli is an attenuated E. coli strain O157:H7.
8. An attenuated enterobacterium comprising an attenuating mutation in the fnr gene and a heterologous nucleic acid sequence encoding a foreign antigen.
9. The attenuated enterobacterium of claim 8, wherein the attenuating mutation is an attenuating deletion mutation.
10. The attenuated enterobacterium of claim 8, wherein the attenuated enterobacterium is an attenuated Salmonella.
11. The attenuated enterobacterium of claim 10, wherein the attenuated Salmonella is an attenuated S. enterica serovar Typhimurium.
12. The attenuated enterobacterium of claim 8, wherein the attenuated enterobacterium is an attenuated Shigella.
13. The attenuated enterobacterium of claim 8, wherein the attenuated enterobacterium is an attenuated Escherichia coli.
14. The attenuated enterobacterium of claim 13, wherein the attenuated E. coli is an attenuated E. coli strain O157:H7.
15. The attenuated enterobacterium of claim 8, wherein the heterologous nucleic acid sequence is incorporated into the bacterial genomic nucleic acid.
16. The attenuated enterobacterium of claim 9, wherein the heterologous nucleic acid sequence is incorporated into the deleted FNR region.
17. The attenuated enterobacterium of claim 8, wherein the heterologous nucleic acid sequence is incorporated into a plasmid.
18. A pharmaceutical composition comprising the attenuated enterobacterium of claim 8 in a pharmaceutically acceptable carrier.
19. A method of inducing an immune response in a subject comprising administering to the subject an immunogenically effective amount of the pharmaceutical composition of claim 1.
20. The method of claim 19, wherein an immune response is induced against one or more Salmonella spp.
21. The method of claim 20, wherein an immune response is induced against S. enterica serovar Typhimurium.
22. The method of claim 19, wherein an immune response is induced against one or more Shigella spp.
23. The method of claim 19, wherein an immune response is induced against one or more E. coli spp.
24. The method of claim 23, wherein an immune response is induced against E. coli strain O157:H7.
25. A method of inducing an immune response in a subject comprising administering to the subject an immunogenically effective amount of the attenuated enterobacterium of claim 8.
26. The method of claim 25, wherein the immune response is induced against the foreign antigen and the enterobacterium.
27. The method of claim 26, wherein an immune response is induced against one or more Salmonella spp.
28. The method of claim 27, wherein an immune response is induced against S. enterica serovar Typhimurium.
29. The method of claim 26, wherein an immune response is induced against one or more Shigella spp.
30. The method of claim 26, wherein an immune response is induced against one or more E. coli spp.
31. The method of claim 30, wherein an immune response is induced against E. coli strain O157:H7.
Type: Application
Filed: Jul 19, 2007
Publication Date: Mar 6, 2008
Applicant:
Inventors: Hosni Hassan (Raleigh, NC), Ryan Fink (Naples, FL), Matthew Evans (Raleigh, NC)
Application Number: 11/780,358
International Classification: A61K 45/00 (20060101); A61P 37/00 (20060101); C12N 1/36 (20060101);
