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Specificities of IgE, IgG and IgA antibodies to ovalbumin. Comparison of binding activities to denatured ovalbumin or ovalbumin fragments of IgE antibodies with those of IgG or IgA antibodies.

We studied the binding activities of IgE, IgG and IgA antibodies in patients with allergy to hen's egg white against two different ovalbumin (OVA) preparations, which were physically or chemically denatured OVA and enzyme-digested OVA fragments. The binding activities of IgE antibodies to these OVA preparations with those of IgG or IgA antibodies were compared. It was found that the binding activities of IgE antibodies to denatured OVA by treatment with dithiothreitol, urea or hydrochloric acid were similar to those of IgG or IgA antibodies. In contrast, the binding activities of IgE antibodies to heat-denatured OVA or by treatment with sodium hydroxide at pH 11.0 were different from those of IgG or IgA antibodies to these denatured OVA. Furthermore, we found that the binding activities of anti-OVA antibodies in sera from patients with allergy to hen's egg white against fragmented OVA were different between IgE antibodies and IgG or IgA antibodies. Thus, it can be concluded that IgE antibodies to OVA in sera from patients with allergy to egg white differ from IgG or IgA antibodies in respect to binding activities against different preparations of denatured or fragmented OVA, probably due to differences in fine specificities of these antibodies against OVA.

Allergens↗

Anti-idiotype antibodies prevent antibody binding to mouse sperm and antibody-mediated inhibition of fertilization.

Antibodies to components of sperm can interfere with sperm function and prevent fertilization by blocking specific steps of gamete interaction. It can be proposed that anti-idiotype antibodies (anti-Ids) that recognize determinants located close to or within the antigen-binding site of an anti-sperm antibody could block antibody binding to sperm antigen and antibody-mediated inhibition of fertilization. To test this hypothesis, rabbit polyclonal antibodies to idiotypic determinants of the monoclonal anti-sperm antibody M42.15 were developed and characterized. Previous studies demonstrated that M42.15 monoclonal antibody (mAb) inhibits fertilization in vitro and in vivo by inhibiting sperm-zona pellucida interaction. Anti-idiotype antibodies to M42.15 mAb (anti-Id M42) were isolated by affinity chromatography on immobilized M42.15 mAb. Binding specificity of anti-Id M42.15 was demonstrated in a solid-phase radioimmune binding assay and by specific immunoprecipitation of soluble M42.15 mAb. Anti-Id M42 competitively inhibited M42.15 mAb, but not P220.2 mAb, binding to mouse sperm, confirming that the anti-Id preparation contained antibodies directed against idiotopes within or adjacent to the antigen-binding site of the mAb. At equimolar concentrations, anti-Id M42 inhibited binding of 125I-labeled M42.15 mAb to sperm by greater than 80%. These results showed that anti-Id M42 efficiently blocked antibody binding to sperm and suggested that anti-Id M42 could be used to neutralize the anti-fertility activity of the M42.15 mAb. When tested in in vitro fertilization assays, anti-Id M42, but not rabbit immunoglobulin, prevented M42.15 mAb-induced inhibition of fertilization. Together, these results show that the inhibitory activity of anti-sperm antibodies capable of interfering with gamete interaction can be neutralized by anti-Id that recognize determinants close to the antigen-combining site of the anti-sperm antibody.

Animals↗

Neutralization of the biological activity of cytokines and other protein effectors by antibody: theoretical formulation of antibody titration curves in relation to antibody affinity.

Patients treated with interferons, other cytokines, or various biologically active proteins may form neutralizing antibodies, which can adversely affect clinical outcome. It is therefore important to understand how antibodies neutralize such soluble protein antigens and how best to quantitate such antibodies. By applying the mass action law to antigen-antibody reactions, we previously developed a mathematical model applicable in two situations: first, for antibodies having low affinity for the antigen concerned (the Constant Proportion (CP) case), and, second, for antibodies having high affinity (the Fixed Amount (FA) case). The results allowed calculation of neutralization titers which were independent of the particular assay method used. Neutralization by antibodies of intermediate affinity, however, requires different mathematical treatment because the mode of neutralization does not fit the two cases mentioned above. In this paper, theoretical neutralization curves were derived, based on the same mathematical model, for antibodies of intermediate affinity. We show that the slope of the neutralization curve relating residual active antigen to the concentration of antibodies is determined by the antibody association constant and the molar concentration of the effector antigen. It is therefore possible to infer the magnitude of the association constant from the observed neutralization curve. We show that values obtained for the neutralization titer of antibodies of intermediate affinity by the use of the formula previously described for the Fixed Amount and Constant Proportion cases may deviate from the theoretically sound values; the magnitude of the deviation can be estimated by applying the formulas described herein. These relationships should apply generally to antibody neutralization reactions with all biologically active soluble protein effector molecules that have a single and nonrepetitive epitope.

Antibodies↗

A common anti-cardiolipin antibody idiotype in autoimmune disease: identification using a mouse monoclonal antibody directed against a naturally-occurring anti-phospholipid antibody.

We have recently produced a series of human monoclonal antibodies reacting with cardiolipin. One of these, H3, a polyspecific IgM/k derived from a normal individual, was used to raise mouse monoclonal antibody to its idiotype. Two anti-idiotypic antibodies, S2.9 (IgG2b) and S2.10 (IgM) were selected for their specific reaction with H3.S2.9 did not react with five other human monoclonal antibodies of IgM/k class despite the fact that these shared some antigen-binding characteristics with H3.S2.9 was able to block the binding of H3 to all of its cross-reactive antigens including cardiolipin, while S2.10 was not. S2.9 was equally efficient in blocking the binding of H3 to three of its cross-reactive antigens, cardiolipin, diphtheria and tetanus toxoids; greater than 90% inhibition could be achieved at an equimolar ratio of H3 to S2.9. The anti-idiotype S2.9 was used to demonstrate the presence of the H3 idiotype in serum. This idiotype was found in amounts greater than that seen in 42 normal individuals, in 30 of 36 patients with systemic lupus erythematosus (SLE), eight of 20 patients with rheumatoid arthritis (RA), 8 of 20 patients with Felty's syndrome as well as 10 of 23 patients with syphilis. Not one of nine patients with drug-induced lupus syndrome had abnormal levels. In patients with SLE and Felty's syndrome there was a good correlation between the amount of anti-cardiolipin antibodies and the amount of H3 idiotype (rs = 0.70 and 0.69 respectively). No such correlation was found in syphilitics or in patients with RA. In patients with SLE the H3 idiotype was present on IgM and IgG anti-cardiolipin antibodies. In 15 of 16 SLE sera with high levels of cardiolipin antibody, S2.9 blocked binding of serum antibodies to cardiolipin by 13-72%, with a mean value of 49%. One patient had a high level of anti-cardiolipin antibody which could not be blocked by S2.9. These results indicate that a mouse monoclonal antibody which reacts with an idiotope in the antigen-binding region of a naturally-occurring phospholipid antibody also defines a common idiotype of anti-cardiolipin antibodies in patients with autoimmune disease.

Antibodies, Anti-Idiotypic↗

Radioimmunoassay with heterologous antibody (hetero-antibody RIA): utilization of highly cross-reactive antibody present in polyclonal antiserum.

To develop a homologous radioimmunoassay (RIA) for a hormone of a small or rare animal often meets difficulty in collecting a large amount of purified antigen required for antibody production. On the other hand, to employ a heterologous RIA to estimate the hormone often gives poor sensitivity. To overcome this difficulty, a "hetero-antibody" RIA was studied. In a hetero-antibody RIA system, a purified preparation of a hormone is used for radioiodination and standardization and a heterologous antibody to the hormone is used for the first antibody. Canine motilin and rat LH were selected as examples, and anti-porcine motilin and anti-hCG, anti-hCG beta or anti-ovine LH beta was used as the heterologous antibody. The sensitivities of the hetero-antibody RIAs were much higher than those of heterologous RIAs in any case, showing that these hetero-antibody RIA systems were suitable for practical use. To clarify the principle of hetero-antibody RIA, antiserum to porcine motilin was fractionated on an affinity column where canine motilin was immobilized. The fraction bound had greater constants of affinity with both porcine and canine motilins than the rest of the antibody fractions. This fraction also reacted with a synthetic peptide corresponding to the C-terminal sequence common to porcine and canine motilins in a competitive binding test with labeled canine motilin. These results suggest that an antibody population having high affinity and cross-reactivity is present in polyclonal antiserum and indicate that the population can be used in hetero-antibody RIA at an appropriate concentration.

Amino Acid Sequence↗

THE FORMATION AND PROPERTIES OF POLIOVIRUS-NEUTRALIZING ANTIBODY. IV. NORMAL ANTIBODY AND EARLY IMMUNE ANTIBODY OF RABBIT ORIGIN: A COMPARISON OF BIOLOGICAL AND PHYSICOCHEMICAL PROPERTIES.

Rabbit sera were found to possess neutralizing activity (normal antibody) to polioviruses and Coxsackie B viruses. This normal antibody showed high specificity in cross-neutralization and absorption tests. It was associated with heat-stable, mercaptan-sensitive, 19S gamma(1)-beta-macroglobulins, which formed weak complexes with the viral antigen. In rare instances, sera with normal macroglobulin antibody, also contained very low activity which was due to 7S gamma(2)-globulins. The neutralization of poliovirus by normal 19S gamma(1)-beta-antibody appeared to follow first order kinetics, and the thermodynamic parameters of this reaction were the same as those of serological reactions employing immune antibody. The electrophoretic mobility, sedimentation properties, sensitivity to mercaptan, thermostability, and avidity of normal and early (up to day 3) immune antibodies to poliovirus were similar, but differed in several respects from those of late immune antibodies. Thus, the available evidence suggested, that earlier reported differences between normal and immune antibodies reflected differences between antibodies of diverse physicochemical properties rather than between normal and immune antibodies per se. It is proposed that the normal macroglobulin antibody is associated with an immunological response to repeated stimulation with minute amounts of antigen.

Alcohols↗

Antisperm antibodies in infertile women: subclass distribution of immunoglobulin (Ig) A antibodies and removal of IgA sperm-bound antibodies with a specific IgA1 protease.

OBJECTIVE: To determine the immunoglobulin (Ig) A subclass distribution of antibodies in the serum and cervical mucus (CM) of infertile women and to evaluate the effect of an IgA1 protease on the removal of sperm-bound antibodies. METHODS: Twenty infertile women with antisperm antibodies in serum (n = 10) or in CM (n = 10) were recruited for this study. Monoclonal antibodies to human IgA1 and IgA2 were conjugated to immunobeads and the IgA subclass distribution of antisperm antibodies was determined for positive serum and CM samples. The effect of an IgA1 protease (isolated from Neisseria meningitidis strain HF13) on sperm-bound antibodies was evaluated by immunobead binding. RESULTS: In serum, IgA1 subclass antisperm antibodies predominated (89%) when compared to IgA2 (11%). In CM IgA1 accounted for 62% and IgA2 accounted for 38% of the total IgA antisperm antibodies. Enzyme treatment was able to reduce dramatically the amount of serum IgA antibodies bound to sperm from 88% to 10%. Similarly, a significant reduction in CM antisperm antibodies was observed after enzymatic treatment with no loss in sperm motility. CONCLUSION: Cervical mucus antisperm antibodies have a higher proportion of IgA2 subclass suggesting a local production of IgA. Specific IgA1 protease treatment is capable of reducing the amount of immunobead-detectable IgA on sperm. Hamster sperm penetration assays are ongoing to determine if this treatment might improve sperm penetration rates with antibody positive sperm.

Antibodies↗

Mouse-specific antibody responses to a monoclonal antibody during repeated immunoscintigraphy investigations: comparison of antibody titres and imaging studies in a rat model.

As a model for human mouse-specific antibody responses in patients undergoing immunoscintigraphy, we have investigated in rats the production of mouse-specific antibodies (MA) to the mouse monoclonal antibody 791T/36. At intervals of between 5 and 16 weeks the rats were given repeated cycles of intravenous (IV) injections of antibody with or without a simultaneous intradermal (ID) injection. The IV dose was 60 micrograms/kg, a dose similar to that used in many clinical immunoscintigraphy studies. The ID injection was 2 micrograms, which mimicks the skin test dose often given in clinical imaging protocols. The study was carried out with both 131I-labelled antibody and with antibody labelled with 111In by diethylenetriamine-penta-acetic acid (DTPA) chelation. MA was measured with a passive haemagglutination assay using sheep red blood cells coated with the monoclonal antibody. Of rats given ID injections of unlabelled antibody at the same time as the IV imaging doses, 9/20 produced MA during 4 cycles of injections. In contrast, only 2/16 rats given only the IV dose produced MA. Both 131I- and 111In-labelled antibody appeared equally immunogenic with 5/18 and 6/18 overall responders, respectively. The production of MA was associated with a significant perturbation in the biodistribution of the IV dose of labelled antibody as seen by gamma-camera imaging of the rats given 111In-labelled antibody. There was clearance of immune complexes to the liver, this organ accumulating up to 90% of the whole body count rate of radiolabel. MA titres of between 1/100 and 1/78,000 caused equal perturbation of biodistribution, although below 1/100 the effect was more variable.

Animals↗

Antibody-dependent cell-mediated cytolysis (ADCC) with antibody-coated effectors: new methods for enhancing antibody binding and cytolysis.

When P388D1 cells are incubated with anti-TNP IgG antibody and centrifuged through a mixture of dibutylphthalate and bis-(2-ethylhexyl)phthalate (1.5:1), large amounts of antibody remain cell bound for at least 20 hr after washing. Incubating cells with antibody in various concentrations of polyethylene glycol also enhances antibody binding compared with control cells incubated with antibody alone. P388D1 cells coated with anti-TNP antibody are potent killers of TNP-conjugated chicken erythrocytes (not coated with antibody). The cytolytic activity increases in proportion to the amount of antibody bound by the effector cells. Lysis is antibody dependent and hapten inhibitable. When mediated by antibody-coated effectors, lysis is less suceptible to inhibition by aggregated IgG than lysis of antibody-coated cells mediated by untreated effector cells.

Animals↗

Suppression of in vitro production of anti-U1-ribonucleoprotein antibody by monoclonal anti-idiotypic antibody to anti-U1-ribonucleoprotein antibody.

We produced monoclonal anti-idiotypic antibody against immunoaffinity purified anti-U1-ribonucleoprotein (RNP) antibody from a patient (K.T.), by the cell fusion procedure. The specificity of monoclonal anti-idiotypic antibody (IgG1, kappa) was determined by inhibition studies. With the monoclonal anti-idiotypic antibody, cross-reactive idiotypes on anti-U1-RNP antibodies from unrelated patients with anti-U1-RNP antibody was detected in 57% of the samples. The anti-idiotypic antibody specifically suppressed the in vitro production of anti-U1-RNP antibody by lymphocytes from the patient K.T., and unrelated patients with a cross-reactive idiotype, in whom idiotype-reactive T cells were demonstrated. The results indicate that anti-idiotypic antibody may modulate the regulation of in vitro anti-U1-RNP antibody production.

Animals↗

Anti-immunoglobulin antibodies. III. Properties of sequential anti-idiotypic antibodies to heterologous anti-gamma globulins. Detection of reactivity of anti-idiotype antibodies with epitopes of Fc fragments (homobodies) and with epitopes and idiotopes (epibodies).

Murine anti-V region antibodies against a human monoclonal protein Gl with anti-gamma-globulin activity and bearing the Wa cross-reactive idiotype were prepared in several strains of mice. Antibodies were obtained that were specific for the Gl idiotype, the Wa cross-reactive idiotype, and for various framework antigenic determinants that were distinguished by a variety of procedures. Synthesis of such antibodies were found to be independent of MHC and Igh gene complexes. These anti-V region antibodies, produced by a majority of mouse strains investigated, also share a cross-reactive idiotype recognized by BALB/c anti-anti-V region Gl antibodies. A fraction of BALB/c anti-anti-V region Gl antibodies displayed human Fc gamma binding activity and, therefore, can be considered homobodies, as described in other systems. Two of the anti-idiotype antibodies obtained in this system exhibited a peculiar property: they interacted not only with their own antigen (IgM Gl), but also with the Fc fragment with which IgM Gl reacts. Thus, A/J anti-V region Gl antibodies bind to the human Fc gamma fragment in addition to IgM Gl. Similarly, a monoclonal CB6 F1 anti-anti-V region Gl antibody interacted with the V region of IgM Gl as well as with the syngeneic anti-V region antibodies. We called these anti-idiotypic antibodies epibodies because they interact with epitopes of the primary antigen. These homobodies and epibodies, obtained by immunization across heterologous barriers, represent new examples of recognition of the internal image of the antigen within the immune system.

Animals↗

Detection of anti-Borrelia burgdorferi antibody responses with the borreliacidal antibody test, indirect fluorescent-antibody assay performed by flow cytometry, and western immunoblotting.

Borreliacidal antibodies participate in the resolution of Lyme disease by clearing Borrelia burgdorferi sensu lato from the host. Detection of borreliacidal antibodies is also valuable for determination of the specific serodiagnosis of Lyme disease. We show in this work that antibody detected by the borreliacidal antibody test did not correlate with antibody detected by the indirect fluorescent-antibody assay or Western immunoblotting. Detection of borreliacidal antibody decreased with elimination of the spirochete from the host in the presence or absence of therapy. By contrast, the antibody responses detected by the indirect fluorescent-antibody assay or Western immunoblotting remained elevated or continued to expand, respectively. This suggests that the borreliacidal antibody test is a prognostic indicator for clearance of the spirochete. Additional investigations with humans are needed to confirm the prognostic potential of the borreliacidal antibody test.

Animals↗

Identification of paramyxovirus-specific haemolysis-inhibiting antibodies separate from haemagglutinating-inhibiting and neuraminidase-inhibiting antibodies. 2. NDV and mumps virus haemolysis-inhibiting antibodies.

Egg-grown Newcastle disease (NDV) and mumps virus were used for preparation of rabbit hyperimmune sera against purified whole virus and projectionless virus particles. These sera and convalescent sera after natural NDV and mumps infections in chickens and human subjects, respectively, were studied in haemolysis-inhibition (HLI), haemagglutination-inhibition (HI) and neuraminidase-inhibition (NI) tests both before and after absorption with Tween 80-ether (TE) treated virus preparations. In addition, neutralization tests using the different sera were carried out. HI and NI antibodies and the major population of neutralizing antibodies in convalescent sera were removed by absorption with TE treated virus material without changing the titre of non-HI HLI antibodies. Rabbit hyperimmune sera directed against projectionless virus particles exhibited HLI antibody titres in marked excess of HI and NI antibody titres, whereas this was not found in sera against whole virus. Absorption with TE treated virus material resulted in removal of all demonstrable antibody activities in sera against whole virus. The corresponding absorption of sera against projectionless particles eliminated HI antibodies without changing the titre of non-Hi HLI antibodies. In rabbit hyperimmune sera, HI antibodies were of primary importance in neutralization tests. After addition of anti-gamma globulin to the test, an efficient neutralization was observed if mumps non-HI HLI antibodies were used whereas this was not found if NDV non-HI HLI antibodies were used.

Animals↗

The effects of anti-idiotypic antibody on antibody production and apoptosis of anti-dsDNA antibody producing cells.

OBJECTIVE: Systemic lupus erythematosus is an autoimmune disease characterized by the production of anti-dsDNA antibody. Because the titer of anti-dsDNA antibody is correlated with disease severity, especially in lupus nephritis, controlling anti-dsDNA antibody production is important in the treatment of SLE. There are many regulatory mechanisms of autoantibody production; one of these is the interaction between idiotype and anti-idiotype antibody (anti-Id). The purpose of the present study was to assess the effect of anti-Id on anti-dsDNA antibody production and apoptosis and to study the mechanism of anti-Id induced apoptosis. METHODS: After anti-dsDNA antibody producing hybridomas were treated with anti-Id, we checked the amount of anti-dsDNA antibody production, the rate of transcription, cellular proliferation, and apoptosis. Also, after treatment with anti-oxidant (N-acetyl-Lcysteine), phorbol esters with calcium ionophore and corticosteroids, we compared their effect on apoptosis with anti-Id. RESULTS: Two types of anti-dsDNA antibody producing hybridomas (G1-2, gamma and kappa chains; M2-10, mu and kappa chains) were treated with anti-Id and it was found that: (1) the amount of anti-dsDNA antibody production decreased; (2) the rate of transcription and cellular proliferation did not decrease; and (3) the level of apoptosis increased. The two cells expressed Fas and Fas-ligand, and the Fas of G1-2 was functional but that of M2-10 was not. The treatment of these cells with anti-Id resulted in no change in Fas-ligand and Bax expression, but the expression of Bcl-2 was decreased. In addition, treatment with antioxidant (N-acetyl-L-cysteine) inhibited anti-Id-induced apoptosis in G1-2 and M2-10. Phorbol esters with calcium ionophore also inhibited anti-Id induced apoptosis in M2-10. Corticosteroids induced apoptosis in both cells and showed similar results with anti-Id induced apoptosis. CONCLUSION: The anti-Id suppressed the production of anti-dsDNA antibody in two cells by inducing apoptosis, as did prednisolone. Furthermore, Bcl-2, oxygen-free radicals and protein kinase C might be involved in the induction of apoptosis by anti-Id.

Animals↗

Comparative study of IgG1 and IgE antibody mediated homologous PCA in the mouse ear. Lack of cross-desensitization of IgG1 antibody mediated PCA to IgE antibody mediated PCA.

To characterize IgG1 antibody and IgE antibody mediated homologous passive cutaneous anaphylaxis (PCA) in the mouse ear, cross-desensitization was studied using a double-sensitizing technique. Mice were sensitized by injecting into their ears a mixture of two kinds of antibodies with distinct antigen specificities, and PCAs were elicited twice with specific antigens at an appropriate interval. The first PCA was elicited with one antigen free from Evans blue dye and the second with the other antigen in the presence of Evans blue to visualize the reaction. The amount of extravasated dye caused by the latter was determined colorimetrically and compared to that of control which did not receive the first challenge. In PCA mediated by IgG1 antibodies, elicitation of the first reaction significantly inhibited the second reaction evoked after 6, 12, or 24 h. Using IgE antibodies, elicitation of the first PCA also significantly inhibited the following reaction. Inhibition of the second reaction was observed 6 h to 12 days after the first reaction. Conversely, IgG1 antibody mediated PCA did not affect the following reaction caused by IgE antibody. These results strongly suggest that alteration of skin mast cells is smaller in IgG1 antibody than in IgE antibody mediated PCA, when reactions with a similar intensity are evoked. Therefore, it is also suggested that the slight reaction of mast cells initiated by IgG1 antibody might be potentiated by another mechanism in IgG1 antibody mediated PCA.

Animals↗

When is a heterophile antibody not a heterophile antibody? When it is an antibody against a specific immunogen.

Heterophile antibodies are antibodies produced against poorly defined antigens. These are generally weak antibodies with multispecific activities. Human anti-animal antibodies that develop as a result of treatments with animal immunoglobulins are antibodies with strong avidities, produced against well-defined antigens. Although heterophile antibodies and human anti-animal antibodies interfere with immunological assays by similar mechanisms, modes for identifying the sources of the antibodies and for circumventing or retarding the interference may differ. Unfortunately, there has not been a well-organized attempt to encourage correct definition of these antibodies. This problem of inexact definition is highlighted by recent articles in this Journal. In the present discussion, we examine the history leading to this problem and discuss the origins and the reasons that the nature of the antibody is important for rectifying the problem. We propose a simple nomenclature for general usage that should appropriately characterize these antibodies in most cases.

Animals↗

[Clinical research of specific IgE and IgG4 antibody in allergic children. Correlation specific IgE antibody to specific IgG4 antibody to food allergen].

We analysed the correlation specific IgE antibodies to specific IgG4 antibodies to food allergens in 150 asthmatic children by Multiple Factor Analysis-Type II and examined the role of both antibodies. The following results were obtained. 1) Of soybean, there was the stronger influence power between specific IgE and IgG4 antibody than the other 2 food allergens. 2) IgE antibody to soybean had the strong influence power to IgG4 antibodies to egg white and cow's milk and IgG4 antibody to soybean had same influence power to IgE antibodies to egg white and cow's milk. So, the specific IgE and IgG4 antibodies to soybean may be play the role of "the bride" between specific IgE antibody group and specific IgG4 antibody group of food allergens.

Adolescent↗

Restoring antibody activity of a monoclonal anti-RNP antibody by dissociative HPLC. Demonstration of blocking antibody binding sites with antigen released from effete hybridoma cells.

In biomedical research, monoclonal anti-nuclear antibodies have a number of advantages over polyclonal antibodies in terms of both specificity and reproducibility. However, there are some potential problems in the preparation of monoclonal antibodies. A well characterized mouse monoclonal anti-ribonucleoprotein antibody (anti-RNP antibody, 2.73) known to function in Western blotting was found to lose this activity when produced in vitro from long term hybridoma cell culture. Whilst it could no longer detect RNP antigen by Western blotting, it could still function effectively in affinity purification of RNP antigen. Further studies suggested that this was due to blocking of antibody binding sites by RNP antigen released from effete hybridoma cells in culture. The activity of the antibody in affinity purification was retained because the antigen was stripped away by repeated elutions with 6 M urea. HPLC gel filtration in the presence of 6 M guanidine was able to restore the antibody activity of the protein A purified monoclonal antibody. This finding has important general consequences for the preparation of monoclonal antibodies against antigens present in hybridoma cell culture media.

Animals↗