Monoclonal anti-idiotopic antibodies against myasthenia-inducing anti-acetylcholine receptor monoclonal antibodies. Preponderance of nonparatope-directed antibodies affecting antigen binding

To analyze components of the idiotypic network in experimental autoimmune disease, we produced 17 isogeneic anti-idiotopic monoclonal antibodies (anti-Id) against two experimental autoimmune myasthenia gravis-producing anti-acetylcholine receptor (anti-AChR) monoclonal antibodies. We studied the binding of five of the anti-Id to the anti-AChR monoclonal antibodies bearing the complementary idiotopes (Id-mAb). They bound with Kd values ranging from 0.06 to 0.86 nM, values comparable to those of Id-mAb:AChR complexes (0.26 and 0.34 nM). All of the anti-Id tested moderately inhibited the binding of AChR to Id-mAb, whereas for each anti-Id, AChR either strongly inhibited anti-Id binding or had no effect on anti-Id binding. Hence, the inhibition of Id-mAb:AChR binding by anti-Id was not reciprocal with the inhibition of anti-Id:Id-mAb binding by AChR. For each anti-Id, the relative affinities of anti-Id and AChR for Id-mAb together with the lack of symmetry of inhibition by anti-Id compared to inhibition by AChR indicate that these two "ligands" are not competitive inhibitors. Consequently, anti-Id and AChR do not bind to overlapping sites on the Id-mAb, suggesting that the observed inhibition is mediated allosterically. This may be a common mechanism of anti-Id:Id binding, which would have important implications for the mechanism of anti-Id-induced suppression.     

Induction of a neutralizing immune response to human respiratory syncytial virus with anti-idiotypic antibodies.

Anti-idiotypic (anti-Id) antibodies were raised in rabbits against monoclonal antibodies that recognized either F glycoprotein 47F or G glycoprotein 63G, 62G, or 74G of the human respiratory syncytial virus Long strain. Anti-Id sera inhibited the virus binding of the immunizing monoclonal antibodies and in some cases the binding of other antibodies reacting with overlapping epitopes. The anti-Id sera also inhibited virus neutralization mediated by the original monoclonal antibodies. Affinity purified anti-Id antibodies were subsequently used to raise a homologous anti-anti-Id response in rabbits. One of the rabbits, inoculated with anti-Id 63G, generated antibodies that reacted with the G protein of respiratory syncytial virus and neutralized the virus to high titers. The antiviral antibodies induced by anti-Id 63G were broadly cross-reactive with strains of the A and B subtypes. However, the specificities of monoclonal antibody 63G and anti-anti-Id 63G were not exactly the same, as indicated by their reaction with escape mutants to antibody 63G. These results demonstrate for the first time the induction of an anti-respiratory syncytial virus response by anti-Id antibodies.     

Monoclonal anti-idiotypic antibodies induce humoral immune responses specific for simian virus 40 large tumor antigen in mice.

Mouse monoclonal anti-Id antibodies were generated against a mouse mAb (Ab-1) preparation specific for SV40 large tumor Ag (T-Ag). Four monoclonal anti-Id preparations each inhibited the binding of the monoclonal anti-SV40 T-Ag Ab-1 preparation to SV40 T-Ag. These anti-Id preparations appeared to recognize similar idiotopes on the monoclonal anti-SV40 T-Ag Ab-1 based on competitive cross-inhibition studies. One of these anti-Id preparations, designated 57B, was examined further for its in vivo modulatory capacity in mice. This anti-Id induced an Ab-3 response in BALB/c mice that recognized SV40 T-Ag (Ag+) and expressed an Id that was shared by the monoclonal anti-SV40 T-Ag Ab-1 preparation (Id+). The Id expressed on the Ab-3 differed from the Id induced in BALB/c mice immunized with the nominal SV40 T-Ag. Furthermore, characterization of the humoral immune response induced by anti-Id immunization indicated that the Ab-3 also recognized different epitopes on SV40 T-Ag when compared to the anti-SV40 T-Ag Ab-1 preparation used to generate the anti-Id. These studies indicate that monoclonal anti-Id can be used to induce humoral immune responses to a viral encoded tumor-associated Ag in vivo with 1) and Id specificity that differs from that expressed on antibodies produced by immunization with the nominal Ag and 2) an epitope specificity distinct from the Ab-1 preparation used for the production of the anti-Id.     

A study of auto-anti-idiotypes to BSA

In order to study the idiotypic relationships between the antibody populations produced in different species during normal immune responses to ordinary protein Ag, we raised immune sera in mice and chickens by using three protein Ag: BSA, keyhole limpet hemocyanin, and diphtheria toxoid. An avidin-biotin ELISA was used to measure idiotypic binding between antibody populations from these sera. We found that the chicken sera contained auto-anti-idiotypes (AAI) against Ag-specific antibodies that were present in the same serum and that co-purified with those antibodies on Ag-Sepharose columns. These AAI were present in secondary response chicken anti-BSA serum at levels comparable with those of the anti-BSA antibody. The chicken AAI also react specifically with Id in mouse anti-BSA serum. The mouse anti-BSA serum completely inhibits the binding between the chicken Id and AAI. This similarity between the Id of whole populations of antibodies produced in two distantly related species, in the absence of any manipulation with idiotypic or anti-idiotypic reagents, suggests that the AAI detected in this way are internal image antibodies. It indicates there is positive selection for such AAI to be internal images.     

Competition between antigen and anti-idiotypes for rheumatoid factors

Many idiotypic determinants on antibody molecules are thought to be located at the antigen binding site, and therefore the interaction between idiotype (Id) and anti-idiotype (anti-Id) is expected to be inhibited by the antigen. We describe two IgG and one IgM rheumatoid factors whose interactions with their respective anti-Id could only be partially inhibited by very large amounts of antigen, i.e., normal IgG. The anti-Id, however, readily inhibited the binding of their respective rheumatoid factors to IgG. The differences in interaction energies resulted in failure of antigen to readily block the Id-anti-Id interaction, and did not mean that the Id was not at the antigen combining site. The association constants for the Id-anti-Id interactions varied from 1.3 to 14.8 X 10(7) M-1, whereas the strength of the rheumatoid factor antigen bond is on the order of 10(5) M-1 for interaction with monomeric IgG. In addition, the anti-Id were able to remove rheumatoid factors that were bound to solid phase IgG, indicating that anti-Id have the potential for disrupting the immune complexes formed by antigen and antibody.     

Independent expression of a regulatory idiotype on heavy and light chains. A further immunochemical analysis with anti-heavy and anti-light chain antibodies

The heavy (H) and light (L) chains of murine monoclonal autoantibody 62 reacting with thyroglobulin independently express idiotypic (Id) determinants that are very similar if not identical with the Id62 expressed on the intact protein. In this report, we describe the production and characterization of rabbit antibodies to isolated H62 and L62 chains to further prove that individual chains express Id62 in an immunogenic form. The results demonstrate that both chains are capable of eliciting antibodies that, after appropriate adsorption, behave like conventional anti-Id62 antibodies prepared against the intact antibody molecule. By direct radioimmunoassay binding, competition of Id binding and Western blot anti-H62 and anti-L62 antibodies identify as Id-positive the same group of IgG1, bind in a reciprocal fashion to H- and L-chains of parental monoclonal antibody 62, and detect Id62-positive polyclonal serum autoantibodies to thyroglobulin. We conclude that monoclonal antibody 62 expresses independently a similar Id on both polypeptide chains and the intact antibody molecule, or its isolated chains, induce qualitatively similar anti-Id responses. These results are discussed in light of the possible structure/function implication such autoantibodies may have within the Id network.     

Thymus-dependent antiidiotype and anti-antiidiotype responses to a dinitrophenyl-specific monoclonal antibody

BALB/c mice were inoculated i.p. with graded doses of a DNP-specific, IgM mAb (designated 57.1). Injection with unmodified 57.1 in the absence of adjuvants resulted in the generation of an anti-Id response (Ab2) and an anti-anti-Id response (Ab3). The generation of serum anti-Id antibodies was found to be thymus dependent. Nude mice immunized with 57.1 were unable to produce a serum Ab2 response above nonimmunized controls whereas euthymic mice receiving identical doses of 57.1 produced strong Ab2 responses. To examine the specificity of serum anti-Id, sera from mice receiving 57.1 were screened against a panel of mAb representing at least five distinct VH gene families. Serum titers were significantly higher against 57.1 than against any of the other antibodies in the panel. Three of the antibodies in this panel bind FD5-1, a monoclonal anti-Id (Ab2) that also binds 57.1. However, sera from mice receiving 57.1 bound 57.1 only. Thus, the serum Ab2 response appears to be highly specific for idiotopes on 57.1. The predominant isotype of these anti-Id antibodies was IgG1. The number of isotypes detected increased in a dose dependent manner with all IgG subclasses having anti-Id specificity in sera from animals receiving the higher doses of 57.1. Further analysis of the serum demonstrated that approximately 8% of the Ab2 response was paratope-specific (inhibitable by the monovalent hapten DNP-lysine). The same sera were analyzed for the presence of Ab3 by binding to the monoclonal anti-Id antibody FD5-1. Lower serum titers of Ab3 were generated in comparison to serum titers of Ab2. Analysis of the binding specificity of the Ab3 response revealed that DNP-BSA was able to partially inhibit the binding of serum IgM and IgG Ab3 to FD5-1. A subset of the Ab3 response. Ab1' that is specific for DNP was observed in a direct binding assay where detectable amounts of DNP binding IgM, IgG1, and IgG3 isotypes were present. We have thus described a complete circuit (Ab1----Ab2----Ab3) of antibodies within the Id network by immunizing animals with an unmodified mAb in the absence of Ag or adjuvants.     

Bovine monoclonal anti-idiotypes induce antibodies specific for a synthetic peptide bearing a neutralizing epitope of bovine herpesvirus 1 glycoprotein gI (gB).

Bovine monoclonal anti-Id mimicking a neutralizing epitope of bovine herpesvirus-1 (BHV-1) glycoprotein gI were developed. An epitope present on the 74K subunit of gI identified by a murine mAb 1E11 was selected for this study. Bovine lymphocytes from the prefemoral lymph node of a heifer immunized with mAb 1E11 were fused with SP-2/0, a nonsecreting murine cell-line. Two bovine x murine hybridomas secreting bovine monoclonal anti-Id specific for the Id of 1E11 were stabilized. These anti-Id inhibited the binding of 1E11 to purified glycoprotein gI in a dose-dependent fashion. Naive mice immunized with the anti-Id produced anti-anti-Id (Ab3) that reacted with BHV-1 glycoprotein gI in a RIA, and neutralized BHV-1 infection in vitro. The Ab3 also showed reactivity to the 74K subunit of authentic gI glycoprotein in a Western blot analysis, and to the synthetic peptide bearing the 1E11 epitope in a RIA. These results substantiate the presence of the population of anti-Ab2 that functionally resemble antibodies specific for the immunizing Ag BHV-1 in Ab3, and demonstrate the ability of these anti-Id to elicit BHV-1-specific antibody response.     

Monoclonal anti-Id antibodies react with varying proportions of human B lineage cells

Monoclonal antibodies to idiotypic determinants are being used with increasing frequency for analysis and treatment of B cell malignancies. In the present study we have compared the idiotypic specificities of a panel of 39 mouse monoclonal anti-idiotype (anti-Id) antibodies developed against 16 monoclonal human immunoglobulins (Ig). The Id cross-reactivities of these antibodies with Ig products of normal and abnormal B cells were examined by immunofluorescence and immunochemical methods. The reactivity patterns of these anti-Id antibodies with a normal population of plasma cells were highly variable in the immunofluorescence assay. Six were reactive with 2 to 10% of normal plasma cells, 30 with 0.1 to 2% of plasma cells, and three with less than 0.1% of plasma cells from blood, bone marrow, spleen, or tonsils. These reactivity patterns were relatively consistent among samples from 23 Caucasian, black, and Oriental adults. Although the reactivities of most anti-Id antibodies in the panel were not restricted to a particular Ig isotype, several were preferentially reactive with a particular heavy or light chain isotype: one IgM-, two IgA-, two kappa-, and three lambda-restricted antibodies. The immunofluorescence data was confirmed by biosynthetic analysis of Id+ molecules produced by a normal plasma cell population. When the reactivity of this panel of anti-Id antibodies with nonhomologous B cell neoplasms was examined, seven of 30 myelomas or leukemia-derived products and one of nine B cell leukemias or lymphomas without paraproteins were found to be cross-reactive with one or two of the anti-Id antibodies. Although clearly significant, the cross-reactivity between the Id of these paraproteins appeared to be of lower affinity than the reactivity of the homologous Id with their respective anti-Id antibodies. The results reveal a remarkable diversity in the specificities of monoclonal antibodies classified by conventional criteria as anti-Id antibodies, and indicate the potential usefulness of a panel of antibodies for analyzing clonal diversity in normal and abnormal B cell development.     

Counterpoint. Cancer vaccines: single-epitope anti-idiotype vaccine versus multiple-epitope antigen vaccine

Anti-idiotype (Id) vaccine therapy has been tested and shown to be effective, in several animal models, for triggering the immune system to induce specific and protective immunity against bacterial, viral and parasitic infections. The administration of anti-Id antibodies as surrogate tumor-associated antigens (TAA) also represents another potential application of the concept of the Id network. Limited experience in human trials using anti-Id to stimulate immunity against tumors has shown promising results. In this “counterpoint” article, we discuss our own findings showing the potential of anti-Id antibody vaccines to be novel therapeutic approaches to various human cancers and also discuss where anti-Id vaccines may perform better than traditional multiple-epitope antigen vaccines. Received: 27 December 1999 / Accepted: 27 January 2000     

Expression and synthesis of cross-reactive idiotypic antibodies by peripheral blood lymphocytes and their suppression by anti-idiotypes in patients with IgA nephropathy.

We have recently described that patients with IgA nephropathy present high serum levels of anti-BSA idiotypic antibodies that were well correlated with the existence of hematuria. Furthermore, these Id were found in circulating and renal deposited immune complexes. In the present work, we examined the expression of surface idiotypic determinants on PBL by flow cytometry and their in vitro production, using as reagent anti-idiotypic antibodies previously well characterized. The presence of cross-reactive Id-bearing cells was observed in 5 out of 6 patients studied, with frequencies ranging from 3 to 12% of lymphocytes. After 7 days of culture, the spontaneous synthesis of idiotypic antibodies by PBL was found elevated in 6 out of 13 (46%) patients. A major Id cell expression and production was noted in patients with active disease as defined by hematuria. The preincubation of PBL with 20 and 50 micrograms of anti-idiotypic antibodies/2 x 10(6) cells for 3 days induced a significant inhibition of cross-reactive Id production in a dose-dependent fashion, with a degree of suppression between 12 and 50% in five out of six patients studied. In the above assays, as negative controls, we used the anti-Id antibodies previously adsorbed on an Id-Sepharose column. On the whole, these results suggest that patients with IgA nephropathy present dysfunctions in the Id-Anti-Id network that could play an important role in the pathogenesis of this disease.     

Anti-immunoglobulin antibodies. II. Expression of individual and cross-reactive idiotypes on syngeneic and homologous anti-idiotype antibodies

Syngeneic anti-(anti-Id) antibodies were prepared against BALB/c anti-A48Id antibodies, BALB/c anti-460Id monoclonal antibodies, and A/J anti-J558 IdI monoclonal antibodies. With these anti-(anti-Id) antibodies we identified cross-reactive idiotypes on syngeneic and homologous anti-A48Id and anti-460Id antibodies. By contrast, tbe idiotypic determinants of A/J anti-J558 IdI monoclonal antibodies were not shared by other syngeneic, homologous, or xenogenic anti-J558 IdI or IdX antibodies. These results suggest that idiotype-antiidiotype reactions that serve as regulatory controls within the immune system are characteristic for each particular antigen system, strain, or species and that such interactions make the system self-limited with respect to the whole antild repertoire.     

Antiidiotypic vaccination against murine coronavirus infection.

Rabbit polyclonal antiidiotypic antibodies were generated against a neutralizing mAb specific for a conformational epitope on the S glycoprotein of murine hepatitis virus, strain A59 (MHV-A59). These anti-Id were directed predominantly against an Id that was undetectable in rabbit and rat anti-MHV-A59 sera and weakly represented in syngeneic and allogeneic antiviral sera. However, some partial idiotypic sharing was observed between the Id-bearing antibody and a mAb with a similar antigenic site specificity. The anti-Id inhibited the virus-binding and neutralizing activities of the immunizing antibody, demonstrating that they recognize paratope-associated idiotopes. Mice immunized with affinity-purified anti-Id developed MHV-A59-specific antibodies that neutralized viral infectivity to high titers. Moreover, these animals survived an otherwise lethal challenge with viral murine hepatitis virus, unlike control mice immunized with normal rabbit Ig. These results indicate that at least a subpopulation of the polyclonal anti-Id could induce a protective immune response directed toward a biologically important MHV-A59 epitope, and demonstrate the feasibility of antiidiotypic vaccination against a coronavirus infection.     

Spontaneous shift of anti-DNA antibody idiotypes in systemic lupus erythematosus

Spontaneous shift in Id expression of polyclonal anti-DNA antibodies in a patient, BS, with SLE was investigated. BS had active lupus nephritis in 1982 and developed central nervous system lupus in 1986 without evidence of active nephritis. Two rabbit polyclonal anti-Id (BS-82 and BS-86 R-anti-Id) were raised against affinity-purified anti-DNA antibodies prepared from 1982 serum (BS-82) and 1986 serum (BS-86), respectively. In addition, murine monoclonal anti-Id was prepared against BS-82 Id. Direct binding assays showed that all three anti-Id had preferential binding to the immunizing anti-DNA antibodies (the homologous Id) and poor binding to anti-DNA antibodies prepared from the different dated sample of BS. This was confirmed by inhibition assays of binding of anti-Id to the homologous Id by various Id. Moreover, inhibition assays of binding of various Id to DNA by the R-anti-Id showed that the R-anti-Id was the most effective inhibitor for the homologous Id. Testing for Id expression in serial (1982 to 1986) serum samples of BS with the R-anti-Id as probes showed that BS-82 Id declined and was undetectable after October, 1984, whereas BS-86 Id was first detectable in July, 1985, and increased by June, 1986. These results clearly demonstrate spontaneous shifts in Id expression of human anti-DNA antibodies. The phenomenon of Id shift should be considered in any future strategy for the diagnosis and therapy of human autoimmune disease by anti-Id.     

Structure and binding properties of a monoclonal anti-idiotypic autoantibody to anti-DNA with epibody activity.

We report the isolation and characterization of a mouse autoanti-idiotypic mAb (D7.4 IgG2a), which is directed against a major public Id (A52 IgG2b) in the murine and human autoimmune response to DNA. The natural anti-Id mAb has been produced in the course of the SLE-like disease in a female NZB/NZW F1 mouse and showed a dual specificity (epibody activity) for the public Id (A52) and for the autoantigen (DNA). The two binding activities were shown to reside in the Fab portion of the epibody and were highly specific for their respective Ag. A complete nucleotide sequence analysis of the D7.4 H and L chain V-region genes combined with computer comparisons to available Ig sequences may suggest a charge interaction between the H chain CDR3 segments of the Id and anti-Id antibodies. The D7.4 epibody may be a component of the self-binding, idiotypically connected network of natural antibodies. Alternatively, it could be elicited against the potentially pathogenic, DNA-containing immune complexes in order to facilitate their removal from the circulation of diseased individuals.     

Tumor idiotype vaccines. VII. Analysis and correlation of structural, idiotypic, and biologic properties of protective and nonprotective Ab2

We have previously generated and used anti-Id mAb (Ab2) to induce protective immunity against the L1210 DBA/2 tumor and for immunotherapy of established tumors. Among various anti-Id that were typed serologically as internal image Ab2 of the mouse mammary tumor virus tumor-associated Ag gp52, only one induced protective immunity and was effective in immunotherapy. In this study we compared the structural, idiotypic, and network properties of the protective and nonprotective antiidiotypic antibodies. The DNA sequence of the variable regions of six anti-Id was determined. The VH sequence of four Ab2, including the protective Ab2, are highly homologous, whereas the VL sequences differ and were assigned to different Vk families. In addition, the DH sequence region of the same four Ab2 are identical, whereas one is highly homologous and another one without homology. Search for amino acid sequence homologies between the Ab2 and gp52 showed the strongest similarities in the CDR2 of the L chain from the protective Ab2. In addition, the CDR2 region also had homology with a T cell epitope on gp52. The biologic basis of effective idiotypic mimicry was studied at the level of Ab3 induced by the Ab2. Id inhibition analysis using Ab3 induced by either protective or nonprotective Ab2, revealed differences. Thus, there is evidence for differences among the Ab1-Ab2-Ab3 cascade induced by protective and nonprotective anti-Id.     

Idiotypic intramolecular help. Induction of tumor-specific antibodies by monoclonal anti-idiotypic antibody with the help of Fc-specific T helper clones

In this study, the mechanism of anti-Id vaccination was investigated by using cloned Th cells and an anti-idiotypic mAb. 2F10, an anti-idiotypic mAb derived from an Igh1-e allotype mouse strain, which induces protection against the L1210/GZL DBA/2 tumor, was used to prime DBA/2 mice. An Fc (Igh1-e)-specific syngeneic Th clone was cocultured in the presence of 2F10 anti-Id with 2F10-Fab-primed B cells. The Th clone responded with proliferation and also provided help for 2F10-Fab-primed B cells to produce antibodies that bind to L1210/GZL and not to P815 tumor cells. Intact 2F10 anti-Id was presented to Fc-specific Th cells by Fab (or Id) primed B cells more efficiently than the fragment mixture (Fab plus Fc) of 2F10 anti-Id, indicating that 2F10-Fab (or Id)-primed B cells capture 2F10 anti-Id through surface Ig receptors. Presenting B cells are sensitive to treatment with chloroquine and must come from H-2 matched mice, indicating that the Ag presentation by Fab-primed B cells to Fc-specific Th cells requires processing and is MHC restricted. Collectively these results outline a mechanism that may operate in anti-Id therapy of tumor-bearing animals by using tumor Ag mimicking anti-idiotypic antibodies. A similar mechanism could be effective in tumor patients immunized with xenogeneic anti-idiotypic antibodies operating under the "intra(Ag) molecular help."     

Murine monoclonal anti-idiotype antibody as a potential network antigen for human carcinoembryonic antigen.

Carcinomas of the gastrointestinal tract are not curable by standard therapies. Thus, new therapeutic approaches for this disease are needed. This study proposes the use of anti-Id mAb as Ag substitutes to induce anti-tumor immunity in gastrointestinal cancer patients. Recently, we have generated and characterized one monoclonal anti-Id antibody, designated 3H1 (Ab2), which mimics biologically and antigenically a distinct and specific epitope of the 180,000 m.w. carcinoembryonic antigen (CEA) primarily expressed in high density by human pancreatic and colonic tumor cells. This epitope is unique to CEA and not present on other CEA-related lower m.w. members of the Ag family also found on normal tissues. The antigenic determinant as defined by the mAb 8019 (Ab1) against which the Ab2, 3H1 was raised, is absent on normal adult tissues by immunoperoxidase staining and haematopoietic cells including granulocytes by flow cytometry analysis. Anti-Id (Ab2) 3H1 induced CEA-specific antibodies in mice and rabbits. The immune sera from both mice and rabbits competed with Ab1 for binding to the colon carcinoma cell line LS174T and inhibited the binding of radioiodinated Ab1 to Ab2. This indicates that anti-anti-Id (Ab3) in mice and rabbits share idiotopes with Ab1 (8019). Furthermore, monoclonal Ab3 that bind to CEA have been generated from mice immunized with 3H1. The Ab3 (both polyclonal as well as monoclonal) immunoprecipitated the same 180,000 m.w. CEA as Ab1 (8019) by Western blotting analysis and showed almost identical immuno-staining patterns as Ab1 on colonic adenocarcinoma tissue sections from several patients. Collectively these data suggest that Ab2 3H1 could potentially be used clinically as a network Ag for immunotherapy of patients with CEA positive tumors.     

Idiotypic and antiidiotypic T and B lymphocytes in myasthenia gravis.

The prevalence of Id and anti-Id T and B cells as measured by their reactivities with two human mAb, one antiacetylcholine receptor mAb and one anti-Id mAb, was studied in 38 patients with myasthenia gravis and in 27 healthy individuals. Id and anti-Id T cells were estimated by enumerating the numbers of cells secreting IFN-gamma in response to 10 pg/ml of the human mAb. T cell stimulation, measured as numbers of IFN-gamma-secreting cells that exceeded the mean + 2 SD of controls, was induced by the Id mAb in 78.9% of the patients and in 7.4% of the controls, whereas the anti-Id mAb-stimulated T cells in 55.3% of the patients and in 3.7% of the controls. The mean value of the Id and anti-Id-reactive T cells in the patients was 18.3/10(5) and 10.1/10(5) PBMC, respectively. B cells secreting IgM antibodies binding to the human mAb were increased in patients with myasthenia gravis compared to healthy controls. Seventy-five percent of the patients and 12% of the controls had B cells secreting IgM antibodies binding to the Id mAb, although 89% of the patients and 16% of the controls had B cells secreting IgM antibodies binding to the anti-Id mAb. The mean value of B cells secreting IgM antibodies binding to Id or anti-Id mAb in the patients were 7.4 cells/10(6) and 5.5 cells/10(6) PBMC, respectively. We conclude that Id and anti-Id T and B cells are present in myasthenia gravis. These methods allow a quantitative estimation of T and B cells with defined specificities and thus a way of mapping the repertoire of lymphocytes.     

Antiidiotypic antibody mimicry of a bluetongue virus neutralizing antigen.

Syngeneic antiidiotypic (Anti-Id) mAb were produced to the Bluetongue virus (BTV) serotype 17 neutralizing mAb. Three anti-Id mAb had the characteristics of an internal image of the Id as demonstrated by 1) the internal image anti-Id mAb were capable of mimicking BTV by blocking the neutralizing activity of the idiotypic neutralizing mAb and 2) the anti-Id mAb bound specifically to the surface of BTV susceptible cells in indirect binding experiments as determined by immunocytochemistry and flow cytometric analysis. The potential application of these internal image anti-Id mAb in this arbovirus system is discussed.