Presence Of Anti-idiotypic Antibodies Research Articles

Anti-idiotypic antibodies reduce efficacy of the attenuated vaccine against highly pathogenic PRRSV challenge

BackgroundThe inability of current vaccines to provide effective protection against porcine reproductive and respiratory syndrome virus (PRRSV) infection is not fully understood. One of the reasons might be the presence of anti-idiotypic antibodies (Ab2s) to the envelope glycoprotein GP5 induced by PRRSV infection since our previous studies demonstrated the presence of auto-Ab2s (aAb2s) in pigs infected with PRRSV. To test this hypothesis, PRRSV negative piglets were injected with a monoclonal Ab2 (Mab2-5G2) and aAb2s that are specific for anti-GP5 antibody, vaccinated with the attenuated PRRSV vaccine CH-1R and then challenged with the highly pathogenic PRRSV HuN4 strain. The animals were evaluated for clinical signs, pathological changes of the thymus and lungs, viremia, levels of serum antibodies and cytokines.ResultsThe piglets injected with Mab2-5G2 or aAb2, and who received the attenuated PRRSV vaccine CH-1R before challenge, produced high levels of anti-N antibodies, IL-2 and IL-4, but low levels of neutralizing antibodies. After PRRSV HuN4 challenge, the animals showed obvious clinical signs, including lung lesions, severe thymus atrophy and decreased production of IL-4 and higher level of viremia.ConclusionWhen anti-GP5 Ab2s are present, the use of attenuated PRRSV vaccine CH-1R against HP-PRRSV infection is not recommended. It can result in poor health status with pneumonia and thymus atrophy.

Failure to detect anti-idiotypic antibodies in the autoimmune response to IA-2 in Type 1 diabetes

The concept that immune responses to self antigens are regulated by anti-idiotypic networks has attracted renewed interest following reports of circulating factors within IgG fractions of serum that impair detection of autoantibodies with autoantigen. Thus, preclearance of sera with bead-immobilised monoclonal autoantibodies to the Type 1 diabetes autoantigen GAD65, or prebinding of serum antibodies to protein A Sepharose prior to addition of antigen, increases immunoreactivity detected in serum samples consistent with the trapping on the beads of anti-idiotypic antibodies that block antibody binding to the autoantigen. The aim of this study was to investigate the presence of anti-idiotypic antibodies to another major target of autoantibodies in Type 1 diabetes, IA-2. As previously observed for GAD65, preadsorption of serum samples with immobilised monoclonal IA-2 autoantibody, or prebinding to protein A Sepharose, resulted in substantial increases in subsequent immunoprecipitation of radiolabeled IA-2 in a proportion of samples. However, control experiments indicated that the increases seen on pre-incubation with immobilized autoantibodies were caused by displacement of the antibody by serum IgG, whereas impaired detection of immunoreactivity in liquid-phase radiobinding assays was the result of formation of insoluble complexes that bind poorly to protein A. The results emphasise the importance of direct demonstration of specific binding of antibodies to the idiotype in the study of idiotypic networks in autoimmunity. Variability between patients in formation of insoluble immune complexes has implications for the design and standardization of autoantibody assays for diabetes prediction.

Protective role of anti-idiotypic antibodies in autoimmunity – Lessons for type 1 diabetes

Circulating autoantibodies to beta cell antigens are present in the majority of patients with Type 1 diabetes. These autoantibodies can be detected before and at time of clinical diagnosis of disease. Although the role of autoantibodies in the pathogenesis of the disease is debated, their presence indicates a dysregulation of the humoral immune response. Mechanisms regulating autoantibodies in Type 1 diabetes are not well understood. In contrast, in other autoimmune diseases there is acceptance that autoantibodies are regulated not only by antigen but also by other antibodies that bind to the antigen-binding site of these autoantibodies (anti-idiotypic antibodies). The proposed purpose of this network is to maintain an equilibrium between autoantibodies and their anti-idiotypic antibodies, preventing autoimmunity, while allowing a robust response to exogenous antigen. Anti-idiotypic antibodies regulate both autoantibody binding and their levels by a) neutralizing autoantibodies, and b) inhibiting the secretion of autoantibodies. Because it has been proposed that the B lymphocytes that produce autoantibodies function as autoantigen presenting cells, inhibiting their binding to autoantigen by anti-idiotypic antibodies may prevent development of autoimmune disease. This hypothesis is supported by the presence of anti-idiotypic antibodies in healthy individuals and in patients in remission from autoimmune diseases, and by the lack of anti-idiotypic antibodies during active disease. We recently reported the presence of autoantibodies to glutamate decarboxylase in the majority of healthy individuals, where their binding to autoantigen is prevented by anti-idiotypic antibodies. These anti-idiotypic antibodies are absent at clinical diagnosis of Type 1 diabetes, revealing the presence of autoantibodies. Type 1 diabetes (T1D) is an autoimmune disease characterized by the dysfunction and destruction of insulin-producing beta cells by autoreactive T cells. Although much progress has been made towards understanding the respective roles of effector and regulatory T cells in this beta cell destruction, the development of autoantibodies to beta cell proteins is widely considered simply a by-product of the autoimmune destruction of the beta cells, rather than having an active role in the pathogenesis. This view is starting to change based on increasing recognition that autoantibodies can have defined roles in other autoimmune diseases, and the emergence of new data on their role in T1D. This exploration of the role of autoantibodies in autoimmune disease has been spurred, in part, by increasing recognition that development of autoimmune diseases is influenced by regulatory antibodies (anti-idiotypic antibodies) directed against the unique binding site of autoantibodies. This review provides an overview of the development and function of these anti-idiotypic antibodies, and present evidence supporting their role in the development of autoimmune diseases. Finally, we conclude this review with a model of the events that may cause loss of anti-idiotypic antibodies and the implications for the development of T1D.

Intravenous immunoglobulin treatment on anti-GM1 antibodies associated neuropathies inhibits cholera toxin and galectin-1 binding to ganglioside GM1

Intravenous immunoglobulin (IVIg) therapy is efficacious in some peripheral nervous autoimmune diseases associated with anti-GM1 antibodies. Numerous mechanisms of action have been proposed to account for the immunomodulatory effects of IVIg in immune-mediated diseases. Up to now, the mechanisms of action of IVIg in pathology associated with anti-GM1 antibodies have not been well documented. In the present study, we discovered that IVIg did not inhibit the binding of anti-GM1 antibodies to its antigen and IVIg perfusions did not reduce anti-GM1 antibodies titers. In this observation, we have the result different from the hypothesis of presence of anti-idiotypic antibodies in different IVIg preparations, and show that IVIg inhibits the binding of cholera toxin and galectin-1 to GM1-expressing cells using flow cytometry. Our results suggest that the correct ratio galactosyl/agalactosyl IgG in IVIg interact with macrophages receptors to down-regulate inflammatory function of macrophages and autoimmune diseases in peripheral nerve system.

Role of the spleen on the pathogenesis of schistosomal periportal (pipestem) fibrosis of the liver: an experimental approach.

Splenectomized and sham-operated mice with chronic Schistosoma mansoni infection were compared for the development of periportal fibrosis (pipestem fibrosis). Although this lesion appeared less frequently in splenectomized mice, it also developed in the absence of the spleen. The time of splenectomy, spleen weight, presence of anti-idiotypic antibodies, the number of eggs in the liver, and the type and size of periovular granulomas in the liver as evaluated by computerized morphometry did not show statistically significant differences between the two groups. It is concluded that the role of the spleen in the development of pipestem fibrosis seems ancillary and that multifactorial influences, including worm burden, hepatic vascular adjustment, and factors associated with the biology of extracellular matrix of the liver, probably play a more significant role.

High-Dose Intravenous Immunoglobulin Treatment of a Pregnant Patient with an Antiphospholipid Syndrome: Immunological Changes Associated with a Successful Outcome

A patient with a history of habitual abortion, deep venous thrombosis, thrombocytopenia, high titer IgG anticardiolipin antibodies and a clearly positive lupus anticoagulant, was treated during her seventh pregnancy with high-dose intravenous immunoglobulins (IVIg) from the third month onwards. Every month, a daily infusion of 400 mg immunoglobulins per kg body weight was given during five consecutive days. The patient's pregnancy ended preterm with a live birth, delivered by caesarian section because of a placental abruption. The 1070 g (P20-P25) weighing girl was in good health, apart from a bradycardia, due to dysfunction of the atrioventricular conduction. Each treatment with IVIg resulted in a slight reduction of both anticardiolipin antibodies and lupus anticoagulant levels and in an increase in platelet count. During the six-month observation period, a gradual decline in antiphospholipid antibodies and an increase in platelet count was found. The potential role of anti-idiotypic antibodies, present in the IVIg used for treatment, was studied. In vitro, IVIg were able to reduce the binding of the patient's anticardiolipin antibodies to cardiolipin coated microtiter plates. The presence of anti-idiotypic antibodies in IVIg was further documented by affinity chromatography and by realtime biospecific interaction analysis (BIA) on a BIA-core instrument. Affinity purified anticardiolipin antibodies were retarded on a column of insolubilized IVIg and a weak interaction was found between IVIg and affinity purified antiphospholipid antibodies, coupled to the BIA-core biosensor. In addition, the same technology revealed increased levels of anti-antiphospholipid antibodies in the patient's plasma following IVIg therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiidiotypic antibodies to sperm in sera of fertile women that neutralize antisperm antibodies.

The presence of antiidiotypic antibodies (ab-2) to sperm was investigated in the sera of fertile, infertile, and virgin women using sperm-specific anti-FA-1 monoclonal antibody Fab'.ab-2 were detected in 71% (17/24) of sera from fertile women and in none (0/12) of the sera from virgin females by the enzyme-linked immunosorbent assay, Western blot procedure, and immunoprecipitation procedure. Sera from infertile women that had antisperm antibodies showed a minimal presence of ab-2, with only three sera (13%, 3/23) demonstrating the presence of low levels of ab-2. The ab-2 present in fertile women were capable of neutralizing the fertilization-inhibitory activity of anti-FA-1 antibody in a concentration-dependent manner in a human sperm penetration assay (SPA) of zona-free hamster oocytes. ab-2 were also capable of inhibiting the binding of antisperm antibodies to the sperm surface as determined by the immunobead binding technique. This is the first report demonstrating the presence of ab-2 in the sera of fertile women that are capable of neutralizing antisperm antibodies present in sera of infertile women. These findings suggest that the inability to detect antisperm antibody activity in the sera of fertile women may be due to higher levels of ab-2 present in these sera than levels found in sera of infertile women, although both groups may be producing antisperm antibody response after sexual exposure to sperm.

ANCA anti-idiotype antibodies and the treatment of systemic vasculitis with intravenous immunoglobulin.

The presence of anti-idiotype antibodies (anti-id) to anti-neutrophil cytoplasm autoantibodies (ANCA) in intravenous immunoglobulin (IVIg) and remission sera from patients with systemic vasculitis, and the use of IVIg as an alternative therapeutic agent in open studies, has suggested a role for idiotypic regulation in the normal control of these disorders. Clinical benefit with IVIg has been reported in 15/16 patients, with sustained remission in eight. The ability of IVIg to produce lasting remission has been associated with a fall in ANCA levels and stimulation of endogenous immunoglobulin production. IVIg has the potential to influence the pathogenetic process in patients with vasculitis at several stages, and an influence on the idiotypic regulation of ANCA may explain the observed clinical responses and point to possible targets for more specific immunotherapy in the future.

Induction of Anti-Idiotypic (ab2) and Anti-Anti-Idiotypic (ab3) Antibodies in Patients Treated with the Mouse Monoclonal Antibody 17-1A (ab1). Relation to the Clinical Outcome — An Important Antitumoral Effector Function?

Forty-three patients with metastatic colorectal carcinoma (CRC) were treated with the unconjugated mouse monoclonal antibody (MAb) 17-1A (ab1) only. The presence of antiidiotypic antibodies (ab2) and anti-antiidiotypic antibodies (ab3) were analyzed using an ELISA technique and a mixed hemadsorption assay respectively. Ninety-five percent (41/43) of the patients developed ab2 both of the IgM and the IgG classes. Forty-seven percent (20/43) of the patients had detectable ab3 after therapy, two of them also before administration of MAb 17-1A. Binding in vitro of ab3 (ab1) to CRC cells could be specifically inhibited by ab1. Ab3 bound to human monoclonal antiidiotypic antibodies and to a goat antiidiotypic antibody (ab2). Both these ab2 were directed against MAb 17-1A (ab1). There was a strong correlation between the presence of ab3 and the clinical outcome. Ab3+ patients survived significantly longer than those who did not develop ab3 antibodies, 80 weeks vs 38 weeks (p less than 0.001). A statistically significant correlation was found between the presence of ab3 and the anti-tumor response (CR + PR + MR + SD) (p = 0.01). Thus, induction of an antiidiotypic cascade seems to be an important antitumor effector function of MAb in the treatment of cancer patients.

Monoclonal rheumatoid factor-secreting cells in a patient with mixed cryoglobulinemia. Homogeneity and stability of the idiotypic production and in vitro idiotypic suppression.

The potential therapeutic value of anti-idiotypic antibodies during B cell proliferations largely depends on the stability of the target Ig idiotopes. We investigated this stability in a clinical condition of so called nonmalignant monoclonal B cell proliferation, mixed cryoglobulinemia. The idiotypic profile of a single IgM kappa monoclonal auto-antibody with anti-IgG activity (rheumatoid factor (RF] which originated from a patient suffering from a nonmalignant mixed cryoglobulinemia was followed over a period of 3 yr. As judged from the reactivity of a panel of five different mouse monoclonal anti-idiotypic antibodies mapping the RF variable regions, there was no idiotypic change in the serum IgM RF. At a cellular level, in vitro stimulation of the patient's PBL gives rise to IgM kappa auto-antibodies that were shown to bear the same idiotypic determinants as the serum IgM kappa. We then investigated the effects of the anti-idiotypic antibodies on the in vitro IgM kappa production. When stimulated with PWM and in the presence of anti-idiotypic antibodies (10 micrograms/ml), the patient's PBL produced less IgM RF (18 to 62% inhibition). The same inhibition of IgM RF production was observed after EBV infection of the patient's PBL (from 19 to 90% inhibition). In both cases, the remaining IgM RF production was idiotypically indistinguishable from the serum IgM RF. The implications of the idiotypic stability and of the results of in vitro idiotypic manipulation could be important in view of both the understanding of nonmalignant cryoglobulinemia and of the possible therapeutic use of anti-idiotypic antibodies in diseases.

Detection of Human Auto-Anti-Idiotypic Antibodies (Ab2)

This study documents, by means of both solid and liquid phase assays, the presence of anti-idiotypic antibodies (Ab2) in the serum of one allergic individual undergoing ragweed immunotherapy. Serum from this individual was collected and F(ab')2 fragments specific for ragweed antigen E (AgE) were prepared (Ab1). These AgE-specific F(ab')2 Ab1, following absorption with normal immunoglobulin, were studied for their capacity to specifically bind autologous Ab2. The binding of Ab1 to Ab2 was demonstrated to be inhibitable by ragweed AgE but not by another allergen (oak) to which the patient reacted. These findings demonstrate the presence and binding specificities of Ab2 in the serum of a ragweed immunotherapy patient and may serve as a model to study the role of Ab2 in the regulation of Ab1 in allergic patients.

An enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM anti-idiotypes directed against anti-HBs molecules

A simple and specific enzyme-linked immunosorbent assay (ELISA) has been developed to detect circulating IgG and IgM anti-idiotypic antibodies directed against anti-HBs molecules using 96-well polyvinyl microtitre plates as the solid phase and HRPO-labelled goat anti-HBs as conjugate. Anti-idiotype reactions were observed in the supernatant portion after precipitation of immune complexes from sera with polyethylene glycol 6000 (PEG). Both IgG and IgM with anti-idiotype activity were detected concurrently in HBsAg-positive sera from HBV-infected patients and asymptomatic HBV carriers. Anti-idiotype activity was absent in HBsAg-negative sera from healthy persons, and in patients with non-A, non-B hepatitis and viral hepatitis A. However, such antibodies could be demonstrated in the sera of two out of eight HBsAg vaccine recipients negative for anti-HBs but in none of 11 recipients positive for anti-HBs after receiving a booster immunising dose of HBsAg vaccine. Those sera showing positive anti-idiotype reactions were free from rheumatoid factor and HBsAg/IgM or BsAg/IgG complex activity. An analysis of anti-idiotype positive sera for anti-HBs, HBeAg and HBV-specific DNA-polymerase activity demonstrated these markers in 20%, 30% and 60% of cases, respectively. The presence of anti-idiotypic antibodies was presumed to permit a more active multiplication of hepatitis B virus.

Production of idiotypic and anti-idiotypic antibodies by BALB/c mice in response to immunizations with glucagon, vasopressin, or insulin: supporting evidence for the network concept.

After immunizations with glucagon or vasopressin, either conjugated to keyhole limpet hemocyanin or adsorbed to polyvinylpyrrolidone, both anti-hormone and anti-receptor activities were detectable in the serum of injected mice. Anti-hormone activity was identified by ELISA techniques; anti-receptor activity, by determining the ability of serum samples to compete with labeled hormone for glucagon or vasopressin receptors on rat liver plasma membranes. Anti-receptor activity appeared only after the peak anti-hormone response to each immunogen had been established, and required intensive immunizations (six to nine monthly injections). The presence of anti-idiotypic antibodies in serum samples containing glucagon or vasopressin anti-receptor activity was confirmed by demonstrating selective binding of such samples to corresponding rabbit idiotypic antibodies. Serum from mice immunized with insulin also contained anti-hormone activity, as determined by ELISA, and anti-receptor activity, as determined by noting insulin-mimicking properties in stimulating glucose transport in rat adipocytes. The anti-insulin receptor activity developed after only one boost with the hormone. These results are consistent with Jerne's network hypothesis in that the glucagon, vasopressin, and insulin anti-receptor activity may be attributed to antibodies produced in mice as part of an idiotypic-anti-idiotypic network.

MLC-inhibiting antibodies in mice after blood transfusions.

Balb/c (H-2d) mice were transfused weekly with 0.1 ml of whole blood from C3H/HeJ (C3H) (H-2k) mice. One and two weeks after each transfusion, mice were bled and the sera were collected and pooled. Serum samples from transfused mice were absorbed with erythrocytes and spleen cells from C3H mice, and then heat-inactivated. The presence of antiidiotypic antibodies in these sera was investigated using the mixed lymphocyte culture (MLC) inhibition test, in which spleen cells from normal Balb/c mice were tested for proliferative responses to x-irradiated C3H stimulator cells in the presence of sera from transfused mice. Sera obtained from transfused mice caused significant inhibition of responses in MLC. This inhibition in MLC was specific for stimulator cells from the blood donor (C3H), and little or no inhibition was observed with stimulator cells from third-party SJL mice. In addition, the inhibitory effect in MLC was specific for responder cells from the recipient Balb/c mice and no inhibition was observed with responder cells from blood donor C3H mice. These results suggest that blood transfusions induce antiidiotypic antibodies that can block the T cell antigen-specific receptors and cause inhibition of responses of the recipient mice to blood donor alloantigens in MLC. Thus in this strain combination, disparate for the entire H-2 region, antiidiotypic antibodies developed after 1 blood transfusion. These findings are in contrast to our earlier published results in which antiidiotypic antibodies developed after 3 transfusions in recipient-blood donor combination incompatible for the K and I regions. These data suggest that the development of antiidiotypic antibodies may be related to the level of histoincompatibility at the H-2 complex between recipient and the blood donor.

Induction of antibodies by blood transfusions capable of inhibiting responses in MLC.

B6AF1 (H-2KbkDbd) mice were transfused weekly with 0.1 ml of whole blood from DBA/2 (H-2d) mice. One week after each transfusion, the mice were bled and the sera were collected and pooled. The presence of antiidiotypic antibodies in these sera was investigated using the mixed-lymphocyte culture (MLC) inhibition test, in which spleen cells from normal B6AF1 mice were treated with sera from transfused B6AF1 mice, washed, and then tested for their responses to DBA/2 stimulator cells. The sera collected following 3 and 4 transfusions caused a significant inhibition of responses in MLC, but sera obtained after 1 and 2 transfusions caused little or no inhibition. This inhibition was specific for stimulator cells from the blood donor (DBA/2) and was not observed against third-party SJL (H-2s) stimulator cells. In addition, the suppressive effect in MLC was specific for responder cells from the recipient B6AF1 mice, and no suppression was observed with responder cells from C3H (H-2k) and SJL mice. Treatment of DBA/2 stimulator cells with the serum caused no inhibition in MLC. The MLC inhibitory activity of the serum decreased gradually from the first to the third week following 4 transfusions, although a significant inhibition was still demonstrable after 3 weeks. These findings suggest that multiple blood transfusions induce antiidiotypic antibodies that can block the T cell antigen-specific receptors and cause suppression of the recipient's responses against the donor's alloantigens in MLC.

Anti-idiotype antibody-dependent cell-mediated cytotoxicity (ADCC) against idiotype-bearing cells

The present report demonstrates that cells expressing idiotypic determinants on their surfaces can be specifically destroyed by anti-idiotypic antibodies acting as inducers of antibody-dependent cell-mediated cytotoxicity. Lysis of surface-idiotype-positive hybridoma cells was effected by mouse spleen cells, mouse peritoneal cells, or human blood mononuclear cells, in the presence of anti-idiotypic antibodies. In order for lysis to occur, the simultaneous presence of Fc receptor-bearing cytotoxic cells and anti-idiotypic antibodies was required. Specificity of lysis was conferred by the anti-idiotypic antibody. Hybridoma cells expressing a different idiotype could not be lysed. Anti-idiotypic antibody-dependent cell-mediated cytotoxicity against 51Cr-labeled cells expressing a particular idiotype could be induced by the specific anti-idiotypic antibodies and inhibited by unlabeled idiotype-positive cells or by idiotype in a soluble form. Cytotoxicity could not be inhibited by the presence of bystander cells or monoclonal antibodies expressing a different idiotype. It is proposed that ADCC lysis of idiotype-positive cells has important implications for understanding the regulation of immune responses by an idiotype-anti-idiotype network. This cytolytic pathway provides an extremely specific and effective mode of control of idiotype-positive cells by anti-idiotype antibody. Previous observations that an intact Fc fragment was necessary for anti-idiotype antibodies to exert suppressive effects in vivo further support this hypothesis.