Abstract: A reagent useful in the determination of an immunoreactive species comprises water-insoluble particles having tracer molecules associated therewith. Bound to the outer surface of the particles are: (i) receptor molecules which are reactive with the species, and (ii) molecules of a protein having a pI less than about 6, and which protein is not reactive with either the species or the receptor molecules. The weight ratio of the receptor molecules to the low pI protein molecules is from about 100:1 to about 1:10. This reagent is useful in agglutination and other immunological reactions. A method of preparing the reagent includes providing a suspension of the particles and contacting them with the receptor molecules and low pI protein so as to attach both to the particles. The protein is present in the suspension in an amount such that substantially all of it is attached to the particles.

Abstract: A specific binding assay, e.g., immunoassay, method and reagent system wherein a structural analog of the label portion of the labeled reagent is included in the reaction mixture to interact with potentially interfering substances in the test sample. The label analog is selected or designed to be substantially inactive in the assay detection system. The invention improves the precision of the assays, particularly homogeneous immunoassays, by significantly reducing or eliminating the variable interaction, e.g., binding, of the labeled reagent by interfering substances in the test sample.

Abstract: Signal to noise ratio of enzyme immunoassays employing peroxidase conjugates can be improved by including polyoxyethylene ether detergent in the assay buffer. Such detergents reduce interference due to blood and also improve sensitivity of assays of blood-free samples.

Abstract: A serum folate assay wherein the serum folate is stabilized with dimercaptosuccinic acid or thioctic acid.

Abstract: A latex agglutination assay to detect antibodies against pseudorabies virus is provided. The test assays swine serum or plasma for the presence of pseudorabies virus antibody which is indicative of an acute or previous infection or vaccination. The latex reagent is a suspension of latex particles, 0.9 microns in diameter, that have adsorbed thereon antigens from disrupted and solubilized pseudorabies virus. When this material is mixed by rotation with serum containing pseudorabies antibodies, the latex will agglutinate forming visible clumps. In the absence of antibody, the latex suspension will remain smooth and evenly dispersed.

Abstract: A method is disclosed for preparing a sample suspected of containing digoxin for determination of digoxin in the sample during an assay. The method comprises contacting the sample with .beta.-cyclodextrin in an amount and under conditions sufficient to allow a substantial portion of digoxin in the sample to bind to the .beta.-cyclodextrin. The .beta.-cyclodextrin with bound digoxin is separated from at least one other component of the medium. Next, the digoxin is released from the .beta.-cyclodextrin to provide a sample containing digoxin which may be analyzed by any of a number of assay techniques.

Abstract: An assay method and kit for a hapten such as theophylline employs a first, latex reagent and a second, antibody reagent. By using a monoclonal antibody of the IgA class in the second reagent, interference by patient rheumatoid factor is prevented.

Abstract: A method for use in the assay of PIVKA-II by the enzyme immunoassay using the two antibody-sandwiching method, characterized by using a monoclonal anti-PIVKA-II antibody as solidified antibody for said assay.

Abstract: A method for quantitative analysis of low molecular weight components which are contained in a protein-containing liquid sample originating from body fluids and are capable of binding to said protein, characterized by incorporating into the liquid sample a compound having the formula (I):X--(Y).sub.p --SO.sub.3 M (I)in which M is hydrogen ion, an alkali metal ion, or ammonium ion; X is a straight or branched alkyl, alkenyl, fluorinated alkyl, or fluorinated alkenyl group containing at least 6 carbon atoms, Y is a divilent organic residue; and p is 0 r 1. The compound represented by formula (I) liberates thyroid hormone from bound protein to facilitate analysis.

Abstract: Antibodies which form immune complexes with human native prothrombin only, in the presence of mixtures of human native prothrombin and human abnormal prothrombin as well as antibodies which form antibody antigen complexes with human abnormal prothrombin in the presence of such mixtures have been obtained. Immunoassay techniques are used for qualitative and quantitative determinations of these antigens in human plasma or serum. Unique methods of obtaining the antibodies are described including obtaining antibodies to native prothrombin by dissociation of antigen antibody complexes formed in the presence of calcium ions with a material having a greater affinity constant for binding with calcium ions than does prothrombin. Dissociation of the complex in this manner yields human native prothrombin antibodies which are specific and non-reactive with human abnormal prothrombin.

Abstract: A method and test kit for the serological diagnosis of human infection by herpes sipmlex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) using immunoaffinity purified virus-coded glycoproteins as target antigens. A preferred embodiment of the method employs a variation of the enzyme-linked immunosorbent assay (ELISA) whereby monoclonal antibodies are used to purify target antigens, and test sera are absorbed with virus-infected cell extracts to remove intertypic cross-reacting antibodies.

Abstract: Method and means in/for the immunoassay determination of (I) a bacterial polypeptide capable of binding to the Fc protion of an immunoglobulin and/or (II) the high affinity antibody to said polypeptide. The characteristic feature of the method resides in using an antibody directed against the polypeptide and having antibody activity under conditions such that the immunoglobulin potentially binding to the polypeptide will substantially not bind to the polypeptide, and carrying out the immune reaction between the antibody preparation and the corresponding polypeptide epitope under such conditions.

Abstract: An method of carrying out a fluorescence polarization immunoassay is disclosed wherein the immunoassay is conducted in the presence of from about 0.001 to about 1.0 percent (weight/volume) of dioctyl sodium sulfosuccinate. Also disclosed are reagents useful in the practice of the immunoassay method.

Abstract: A method for determining low density lipoproteins (LDLs) in a body fluid sample, as well as a reagent suited for this use, are taught. The method involves precipitating high density lipoproteins (HDLs) from the sample, using an HDL specific antibody or reactive fragment, and then determining the presence and amount of LDL in the supernatant which results. The reagent contains the HDL specific antibodies, as well as polyanions and divalent cations.

Abstract: A blood fluid composition for use in a complement-mediated cell lysis system. The composition includes a blood fluid, which may be either a serum source of complement, analyte-containing serum, or both, and lipid vesicles capable of reducing the extent of non-specific cell lysis produced when the blood fluid is added to lysable target cells in the system. The vesicles are present in an amount which increases the ratio of ligand-specific to non-specific cell lysis in the system at least 2-fold and preferably 4-fold or more over that achievable in the system in the absence of the vesicles.

Abstract: The present invention provides a process for the detection of redox reactions by introducing a redox reagent system into a test system, wherein a soluble iodate is additionally added to the test system in an amount which is in excess of the highest amount of disturbing reducing agents present in the test system.The present invention also provides a diagnostic agent for the detection of redox reactions containing a redox reagent system, wherein the test system used additionally contains an iodate which is soluble therein in an amount which is in excess of the highest amount of disturbing reducing agents present in the test system.

Abstract: Detection of an identified human carcinoma tumor antigen in a pathological sample by means of a labelled monoclonal antibody specific to the determinant site on the antigen is enhanced and/or accelerated at an earlier development stage than heretofore achieved by removing a carbohydrate steric hindrance for monoclonal antibody availability to bind the antigen of the tumor for which it is specific. The carbohydrate steric hindrance for monoclonal binding to the antigen is identified as sialic acid. The method of the invention involves selective removal of sialic acid from the antigen's determinant site by enzymatic digestion using neuraminidase.

Abstract: A process for producing an antibody having a specificity to estriol-3-sulfate, which comprises administering a 6-substituted-estriol-3-sulfate protein conjugate of the formula: ##STR1## wherein A is .dbd.N--O-- or --O--CO--, n is an integer of 1 to 4 and --NH--P is the residue of a protein excluding a hydrogen atom in the amino form therefrom parenterally to a living body of a vertebrate animal so as to produce the antibody in the living body and collecting a body fluid comprising the antibody from the living body.

Abstract: A method for assaying for a ligand analyte which is a member of a specific binding pair ("sbp member") consisting of ligand and its complementary receptor is disclosed. The ligand analyte has a binding site in common with an interfering substance present in a sample suspected of containing the analyte. The interfering substance has at least two binding sites. The method comprises combining in an assay medium without intervening separation (1) the sample, (2) a blocking receptor which does not bind to the ligand and does bind to the interfering substance, thereby blocking the binding of a common receptor to the interfering substance, and (3) a common receptor which binds to the common binding site. Any additional members of a signal producing system capable of producing a detectable signal in relation to the amount of analyte in the sample are added to the assay medium. Next, the assay medium is examined for the presence of a detectable signal.

Abstract: Interfering proteins are precipitated and digoxin extracted in a fluorescence polarization immunoassay for digoxin with a protein precipitating reagent. The reagent contains about 3 to 4% 5-sulfosalicyclic acid in an aqueous solution including about 40 to 60% of a straight or branch chained organic alcohol having from 1 to 4 carbon atoms.

Abstract: A method is disclosed for the determination of human serum factors which are specific for human carcinomata antigens, in which method the serum of a patient with a carcinoma is incubated with CEA that has been radioactively labeled and anti-goat immunoglobulin serum in toto or depleted of the cross-reaction capacity for human IgA, IgG and IgM is added, then the whole mass is incubated and centrifugated, the supernatant is decanted and the precipitate is counted with a gamma counter. These specific serum factors are employed as a marker of primitive tumoral forms.

Abstract: A method for assaying complement fragment C.sub.3 a, C.sub.4 a or C.sub.5 a or the des-Arg derivative thereof in a biological sample which comprises combining equal volumes of the biological sample and a solution of 0.8 to 1.6% of an acridine derivative selected from the group consisting of acrinol, acriflavine, acriflavine hydrochloride, and aminacrine, incubating the mixture for about one minute to 2 hour at about 25.degree. C., recovering the supernatant from the resultant precipitate, incubating the supernatant with a known amount of a labeled complement fragment selected from C.sub.3 a, C.sub.4 a or C.sub.

Abstract: A process for the detection and assay of a biological substance by erythroadsorption by immobilizing a substance having a binding affinity for the biological substance to be assayed; incubating the immobilized substance with a liquid medium containing the biological substance to be assayed, forming a fixed substance; incubating the fixed substance with a coupling product comprising a specific ligand and a second ligand which binds with erythrocytes; adding erythrocytes; and determining the amount of erythrocytes bound to the coupling product. The determination of the amount of bound erythrocytes can be made visually with the naked eye or determined by lysis of the erythrocytes bound to the coupling product and quantitatively measuring the released hemoglobin. The specific ligand can be an antibody or an antigen and the second ligand capable of coupling erythrocytes can, for example, be red blood cell antibodies.

Abstract: A process of immunoassay of a selected substance in a liquid sample containing one or more other non-selected substances, each of these substances being comprised of at least two structurally different chains, the process comprising among others addition of a dissociating agent, such as for example a proteolytic enzyme, to the sample, mixing of the so-obtained liquid, inactivation of the dissociating agent, addition of antiserums, and determination of the amount of this selected substance in the liquid sample.

Abstract: An anti-I sorbent which comprises as I blood group substances at least two materials selected from the group consisting of mucin and milk derived from Eutheria and ovomucoid from Ornithurae. The use of the anti-I sorbent inhibits the formation of false positive agglutination caused by anti-I autoantibody.

Abstract: A newly discovered family of AIDS-associated viruses, designated ARV, is described. The viruses were isolated from AIDS patients from San Francisco and (a) are type D retroviruses; (b) have Mg.sup.++ -dependent reverse transcriptase activity; (c) induce human multinucleated cells without immortalizing the cells; (d) are replicable in HUT-78 human T cells; and (e) induce viral protein(s) in HUT-78 that binds to Ig from AIDS patients. The infected HUT-78 cells and immunogenic polypeptides derived from the viruses are useful for diagnosing AIDS.

Abstract: A method for rapidly determining the presence of functional cellular steroid receptors by assaying a tissue sample for nuclear steroid binding is disclosed which comprises treating the tissue with collagenase, incubating the isolated cells with a labelled steroid capable of complexing said receptors and measuring the bound radioactivity and the DNA of the isolated cellular nuclei.

Abstract: The performance of immunoassays for the analysis of serum analytes can be significantly improved by the pretreatment of the sample. Analyte in serum samples is often complexed with serum antibody. Such analyte-antibody complexes can mask the analyte and interfere with analyte specific binding steps of many immunoassays. The serum pretreatment method employs pH dependent chaotropes to dissociate the analyte-antibody complexes in the serum. At low pH, the complexes become dissociated and the antibody becomes denatured. After the dissociation and denaturation of the serum antibody, the serum sample and the chaotrope, contained therein, are then neutralized. Since the serum antibody has been denatured, it does not re-associate with the analyte upon neutralization. After the neutralization step, serum sample can then be analyzed by an immunoassay, without interference from serum antibody. A serum pretreatment kit is essential to the employment of the serum pretreatment method.

Abstract: A method for determining total digoxin levels in a biological fluid sample containing digoxin-protein complex which method comprises disrupting the digoxin-protein complex by treating said sample solution with an effective amount of a dissociation agent selected from one or more members of the group consisting of a C.sub.3 -C.sub.26 saturated or unsaturated fatty acid, a C.sub.2-7 lower alkanol, quinidine and .alpha.-tocopherol so as to release the bound digoxin from serum protein, passing the treated sample solution through a centrifugal ultrafilter so as to selectively pass digoxin containing sample solution through said filter and retaining said serum proteins and determining the digoxin contents in said sample solution in a fluorescence polarization assay. A kit for carrying out the method is provided.

Abstract: Lipid-dependent diagnostic assays are provided wherein the test sample to be assayed is pre-incubated with one or more phospholipids having a hexagonal (H.sub.II) organization, with lipidic particles, or with bilayer-forming lysophospholipids such as monooleoylphosphatidylethanolamine (MOPE). The pre-incubation results in reduced false positives due to antiphospholipid antibodies, such as, lupus anticoagulants, which may be present in the test sample, without changing the overall character, including the normal baseline, of the assay. Surprisingly, in accordance with the invention, it has been found that only hexagonal phospholipids, lipidic particles, and bilayer-forming lysophospholipids can be used, and, in particular, lamellar (bilayer) phospholipids (other than such lysophospholipids) cannot be used. An assay for diagnosing systemic lupus erythematosus (SLE) is also provided.

Abstract: A method for immunoassay of an analyte in a fluid includes contacting the analyte with an antianalyte to give a bound fraction. The bound fraction activates the first component of complement whereby a substrate present in the fluid is modulated to provide a detectable signal. The signal may be detected to establish the presence or absence of the analyte in the fluid, or it may be quantitatively measured to determine the concentration of the analyte in the fluid. The invention includes a kit of materials useful in performing the method of the invention.

Abstract: A procedure for detecting malignancy includes culturing human colon tumor cells in a capillary system. A rabbit is immunized with byproducts of the culture. An antibody produced in the rabbit is labeled with .sup.125 I using lactoperoxidase according to a known method. Blood samples are drawn from a being to be tested. The drawn blood is processed to produce serum. The immune complexes are removed from the serum with purified protein A from the Staphlococcus Aureus Cowan strain. The removed immunocomplexes are dissociated with 0.2M glycene/HCl pH 2.8. The labeled antibody is combined with the antigen component of the immunocomplex to produce a new labeled immunocomplex. The newly formed immunocomplex is precipitated with PEG 6000. The newly formed labeled immunocomplexes are counted in a gamma auto counter.

Abstract: In an immunoassay, ultrafine particles having an average particle size of 0.2 .mu.m or smaller and sensitized with a substance, which has reactivity with the materials to induce a nonspecific immunoreaction, are added to a sample to inhibit the nonspecific immunoreaction. The above immunoassay can avoid the influence of nonspecific factors more effectively, thereby permitting accurate measuremens on the concentrations of antigens in samples such as blood, urine, body fluid and the like.

Abstract: A method for obtaining fetal cells for diagnostic examination comprises removing detached cells from the uterine cavity and outer surface of the amnionic sac. The cells are then incubated in the presence of a separation antibody which binds preferentially to either fetal cell antigens or maternal cell antigens for a time sufficient to permit antibody-antigen binding to occur. Cells having said separation antibody bound thereto are separated for the mixture. The separation antibody can be an anitbody binding preferentially to fetal cell antigens and not significantly to maternal cell antigens or it can be an antibody binding preferentially to maternal cell antigens and not significantly to fetal cell antigens. The antibody can be bound to an insoluble support prior to the incubation, and separation can be effected by separating the insoluble support from the cell mixture following the incubation.

Abstract: Background interference which disrupts the measurement of an analyte in enzyme immunoassays with samples is substantially diminished. In accordance with one embodiment of the invention, the serum sample is treated with a sufficient amount of a peracid compound, either organic or inorganic, for a time and under conditions sufficient to reduce or eliminate background interference contributed by serum components other than analyte. The peracid compound is readily quenched, without adversely affecting the assay compositions. In another embodiment of the invention a liqand for the interfering component of the sample, such as unconjugated enzyme which is inactive but antigenic, is mixed with the sample to be analyzed. The presence of the liqand substantially reduces or eliminates background interference from components of the sample other than analyte.

Abstract: A biochemical detection method in which a ligand is bound to a surface, an aqueous solution containing an antiligand is brought into contact therewith whereby antiligand becomes bound to ligand, the aqueous solution is separated from the thus bound antiligand, and the antiligand is detected using a detection means associated therewith, for example using amplified enzyme-linked immunoassay. The surface is treated with at least one agent for limiting non-specific binding of either the ligand or the antiligand with other substrates, which agent is(i) a surfactant containing an aromatic residue and having an HLB number of at least 16,(ii) a zwitterionic surfactant, or(iii) a solution containing a salt of a polyvalent anion, in a concentration of at least 100 mM.Preferably, all three agents are used simultaneously. The three agents may be used during the detection procedure in solutions containing the antiligand, in washing solutions used during the method, or in solutions used to pre-treat the plate.

Abstract: Improved lipid-dependent diagnostic assays are provided wherein the test sample to be assayed is pre-incubated with one or more phospholipids having a hexagonal (H.sub.II) organization or with lipidic particles. The pre-incubation results in reduced false positives due to anti-phospholipid antibodies, such as, lupus anticoagulants, which may be present in the test sample, without changing the overall character, including the normal baseline, of the assay. Suprisingly, in accordance with the invention, it has been found that only hexagonal phospholipids and lipidic particles can be used, and, in particular, lamellar (bilayer) phospholipids cannot be used. An assay for diagnosing systemic lupus erythematosus (SLE) is also provided.

Abstract: A method of specimen treatment preparatory to conducting an immunoassay is disclosed whereby a microbial protein is solubilized by a detergent at elevated temperatures and in the presence of an alkali or alkaline earth metal ion. At elevated temperatures, the detergent is soluble. However, at lower temperatures, the presence of the metal ion renders the detergent insoluble so that it is prevented from interacting in the immunoassay procedure. A specific application is in the solubilization of the principal outer membrane protein of Chlamydia trachomatis.

Abstract: Viruses are detected by means of an immunoassay method in which an extended solid phase coated with antiviral antibody is employed to bind and remove virions from a specimen by forming an immuno-complex with antigens of said virions, a mobile solid phase comprising a dispersion of microspheres coated with the antiviral antibody is used to bind said microspheres to antigens associated with said immuno-complex, and the presence of bound microspheres is detected. The detection sensitivity is amplified by the ability to more readily detect the microspheres, which may be dyed or labelled. The extended solid phase advantageously may be in the form of a dipstick which can be easily contacted with the specimen. A virus detection kit provides the extended solid phase and mobile solid phases, each coated with antiviral antibodies.

Abstract: A competitive enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies is disclosed. This ELISA technique is more sensitive, more specific, and more accurate than known ELISA techniques. The competitive ELISA of this invention is particularly suited to the detection of human T-cell leukemia-lymphoma virus type III (HTLV-III). Antigenic or viral fragments are bound to a solid support. The bound fragments are then incubated with a heterologous antiserum which binds to the bound fragments. Test sera is then added to the bound fragments and tested for absorbance.

Abstract: A method for detecting an antigen in a plasma or serum sample, which comprises conditioning the sample, wherein conditioning comprises either diluting the sample by a factor of at least 100 or dissociating the antigen in the sample from binding proteins with acid, base, or a chaotropic agent; drying the conditioned sampled; and detecting the antigen in the dried sample using an immunological assay is disclosed. The method is particularly useful for the detection of antigens associated with breast cancer.

Abstract: Serum is passed through a column containing silica gel alkylated with lower alkyl groups. The column is then washed with diluted acid and water, and the digoxin eluted with aqueous methanol at a volume less than about the volume of the serum to provide a digoxin concentrate that may be used in assay determinations.

Abstract: A radioimmunoassay method for the determination of brain antigens or protein such as S-100 responsible for neurological disorders is disclosed. The method involves preparing a standard blood plasma or serum formulation containing substantially none of the protein being assayed and approximately the average degree of non-specific competitive binding found in the unknown blood sample and mixing known quantities of the protein being assayed with the standard blood formulation to provide a reference standard. The unknown blood sample is then mixed with a radioactively labeled sample of the protein being assayed and an antibody capable of immunoreactivity with the protein, the mixture is incubated, the antibody bound protein is separated from the unbound protein and the relative amounts of antibody bound and unbound protein are determined.

Abstract: A solution containing from about 0.25% to about 5% hydrolyzed ovalbumin by weight provides surprising thermal stabilization of monoclonal antibodies.

Abstract: A specific binding enzyme-resistant ligand assay test material, which material comprises (a) a solid phase incorporated with one partner of a specific binding pair comprising said ligand or a binding analog thereof and a specific binding protein therefor; (b) a conjugate comprising the other partner of said specific binding pair incorporated with a substance which protects the specific binding protein of said pair from enzyme inactivation when bound with its partner; and (c) an active protein-inactivating enzyme. Also a specific binding method of assaying for an enzyme-resistant ligand in a sample, which method uses the above test material and which results in a reduction in interference caused by non-specific protein.

Abstract: The invention is an improvement in a heterogeneous immunoassay, and reagent therefore, for the determination of a substance in a blood serum or plasma sample, such as a parnter of an immune reaction, in which one of the reaction partners is adsorbed on a solid carrier, the improvement comprises adding a detergent to the incubation medium of the reaction, in an amount of 0.0001 to 0.01% (w/v) to reduce interferences from the serum or plasma.

Abstract: A process of carrying out a specific binding assay, for the qualitative detection or quantitative or semi-quantitative determination of an analyte which forms a component of a specific binding reaction, using a labelled conjugate form of a derivative or analogue of one of the relevant specific binding partners, said labelled form being capable of emitting delayed luminescence upon photo-excitation, characterized in that the labelled conjugate form of one of the relevant specific binding partners comprises a derivative or analogue of the specific binding partner with a derivative of a luminescent substance which shows a delayed light emission upon photoexcitation, the delayed light emission of which is subject to quenching by molecular oxygen, and characterized further in that the assay is carried out by the use of a time-resolved photometric method in the presence of an effective amount of a quench-inhibiting substance able to prevent quenching by molecular oxygen.

Abstract: Process for the determination of carcinoembryonic antigen (CEA) in a sample of serum or plasma. The process comprises contacting a slightly acidic buffered sample of the serum or plasma with hydrophilic silica at room temperature, separating the silica from the sample and carrying out a radioimmunoassay for carcinoembryonic antigen on said sample.

Abstract: At the conclusion of a selective binding assay (e.g., immunological or nucleic acid), an enzyme is present in modulated concentration and/or activity to moderate a chemical reaction such as the cleavage of o-nitrophenyl-.beta.-D-galactopyranoside. After a controlled period, the enzymatic product is transferred to the gas phase and concentrated relative to other components in the enzymatic reaction mixture, such as by extraction into ethyl ether, injection into a gas chromatography column and detection by flame ionization or electron capture. Kits for such assays are also disclosed.

Abstract: A process for conducting fast, rapid two site, two step immunoradiometric tests for CK-MB.In a first series of steps, a mobile particulate solid-phase having an isoenzyme selected from the group of CK-BB and CK-MM immobilying bound on its surface is suspended in a matrix of pooled match human serum. The mixture is incubated, diluted, and centrifuged.In a second series of steps, the resulting solid is incubated with a radio labeled antibody that is specific to the isoenzyme not used in the first series of steps. Counting the radioactivity gives the amount of CK-MB in the patients serum.