Idiotype network components are involved in the murine immune response to simian virus 40 large tumor antigen

Summary Baculovirus-derived recombinant simian virus 40 (SV40) large tumor antigen (SV40 T-Ag), a monoclonal antibody specific for SV40 T-Ag (Ab-1 preparation), and a monoclonal anti-idiotypic antibody (anti-Id), designated 58D, were used to analyze the humoral immune response of Balb/c mice either immunized with recombinant SV40 T-Ag or challenged with SV40-transformed cells. Inhibition assays indicated that antibodies from mice immunized with SV40 T-Ag and from those bearing SV40 tumor inhibited the SV40 T-Ag/Ab-1 reaction. These data suggested that the antibody response in immunized or tumorchallenged mice recognized similar epitope(s) on SV40 T-Ag to that detected by the monoclonal Ab-1. These anti-(SV40 T-Ag) response antibodies also inhibited the Ab-1/anti-Id reaction and recognized the anti-Id in direct binding assays. Together, these data indicate that murine anti-(SV40 T-Ag) responses shared an idiotope with a monoclonal anti-(SV40 T-Ag) Ab-1 preparation. This idiotope, which is recognized by the monoclonal anti-Id preparation, 58D, appears to be involved in the humoral immune response to SV40 T-Ag in both SV40-T-Ag-immunized and tumor-bearing mice. The monoclonal anti-Id preparation may represent a focal point for manipulating the humoral immune response to tumors induced by SV40-transformed cells.     

Comparison of the murine humoral immune response to recombinant simian virus 40 large tumor antigen: Epitope specificity and idiotype expression

Baculovirus-derived recombinant simian virus 40 (SV40) large tumor antigen (SV40 T-Ag) was used to immunize inbred strains of mice to compare the humoral immune responses. Specifically we examined the epitope specificities and idiotype (Id) expression on anti-(SV40 T-Ag) responses induced in BALB/c and C57BL/6 inbred strains of mice. The predominant SV40 T-Ag epitopes recognized by the anti-(SV40 T-Ag) responses appeared to differ between these two inbred strains, this being based on the ability of sera to inhibit the binding of several murine monoclonal antibodies specific for SV40 T-Ag. In addition, anti-(SV40 T-Ag) responses produced in C57BL/6 mice failed to express a previously described cross-reactive Id expressed in the anti-(SV40 T-Ag) response in BALB/c mice. This cross-reactive Id is detected by a mouse monoclonal anti-Id, designated 58D, which has been shown to represent a potential focal point for manipulating the humoral immune response to SV40-induced tumors in BALB/c mice. Together, these data indicate that the functional duality of the humoral immune response, as assessed by epitope recognition and Id expression, differs between these two inbred strains of mice when immunized with a recombinant SV40 T-Ag.     

Induction of an anti-hepatitis B surface antigen response in mice by noninternal image (Ab2 alpha) anti-idiotypic antibodies

Anti-idiotype antibodies to a mouse monoclonal antibody A-12 directed against HBsAg were produced in rabbits. The anti-Id consisted of an Ab-2 alpha preparation that did not display any detectable internal image activity. Immunization of BALB/c mice with the anti-Id (Ab-2 alpha) coupled to KLH induced an anti-HBs response without subsequent HBsAg exposure. No anti-HBs was detected in control groups of mice immunized with other rabbit anti-Id-KLH preparations. The anti-HBs containing sera from mice immunized with the Ab-2 alpha were able to inhibit the Id-anti-Id reaction, indicating that an Id-positive, anti-HBs response was induced. This idiotype is not normally expressed during the murine immune response to HBsAg and suggests that noninternal image anti-Id activates silent clones. This study, along with our previous results obtained with the use of internal image anti-Id, suggests that there is more than one Id network operational during the BALB/c murine immune response to HBsAg.     

Collagen-Induced Arthritis Suppressed with Monoclonal Anti-Idiotypic Antibody

In foregoing work, we identified at least 5 distinct epitopes on human type II collagen (CII), using 8 murine monoclonal antibodies (mAb) against human CII, and suggested that a species-nonspecific epitope on CII recognized by anti-CII mAb termed 1-5 is an arthritogenic epitope. We also found that antibody response against a selected epitope of human CII could be induced by immunization with rabbit anti-idiotypic (Id) antibody against anti-CII mAb. The author developed and characterized monoclonal anti-Id antibodies against 1-5 mAb recognizing a putative arthritogenic epitope. The author also investigated whether the anti-Id mAb could regulate antibody response directed against a selected epitope recognized by 1-5 mAb, and the induction of collagen-induced arthritis in DBA/1J mice. DBA/1J mice intravenously preinjected with anti-Id mAb to 1-5, did not produce anti-CII antibody expressing 1-5 Id upon immunization with human CII. Furthermore, as the development of collagen-induced arthritis (CIA) in DBA/1J mice pretreated with anti-Id mAb to 1-5 was significantly suppressed, anti-Id mAb will be a useful tool for studying the regulation of antibody response to a selected epitope. This study lends support to our hypothesis that the 1-5 epitope is an arthritogenic epitope.     

Immune response to human immunodeficiency virus. In vivo administration of anti-idiotype induces an anti-gp160 response specific for a synthetic peptide

Anti-idiotypic antibodies (anti-Id) to chimpanzee antibodies directed against a synthetic peptide corresponding to a native epitope associated with gp41 of human immunodeficiency virus (HIV) envelope glycoprotein were produced in rabbits. The peptide was analogous to amino acid sequences 735 to 752 from the human T cell leukemia virus-IIIB isolate of HIV. Characteristics of the anti-Id preparation included: 1) detection of a shared determinant present on a second chimpanzee and one of three rabbit antibody preparations directed against the synthetic peptide, 2) failure to recognize an idiotype (Id) in BALB/c mouse antisera to the peptide, and 3) partial inhibition of the homologous chimpanzee Id preparation from binding either peptide or a recombinant HIV gp160 preparation. Immunization of BALB/c mice with the anti-Id induced an antipeptide response which bound a recombinant gp160 preparation without subsequent peptide or gp160 exposure. The anti-gp160 containing sera from mice immunized with anti-Id were able to inhibit the Id-anti-Id reaction indicating that an Id-positive antibody response was induced. This Id is not normally expressed in the murine anti-gp 160 immune response to the synthetic peptide and suggests that this anti-Id may activate normally silent clones. This study indicates that Id networks may be operational during the immune response to HIV epitopes. Alternatively, anti-Id may be useful in altering the serologic characteristics of an antibody response to HIV and may offer potential for modulating the immune response in this viral infection.     

Comparison of simian virus 40 large T antigen recombinant protein and DNA immunization in the induction of protective immunity from experimental pulmonary metastasis

In this report we examine the ability of a recombinant tumor antigen preparation to prevent the establishment of experimental pulmonary metastasis. Baculovirus-derived recombinant simian virus 40 (SV40) large tumor antigen (T-Ag) was injected into BALB/c mice followed by challenge with an intravenous injection of syngeneic SV40-transformed tumorigenic cells. The experimental murine pulmonary metastasis model allows for the accurate measurement of metastatic lessions in the lungs at various times after the challenge, using computer-assisted video image analysis. Following challenge, lung metastasis and survival data for the groups of mice were obtained. Animals immunized with recombinant SV40 T-Ag showed no detectable sign of lung metastasis and survived for more than 120 days after challenge. Antibodies specific for SV40 T-Ag were detected in the serum of immunized mice by enzyme-linked immunosorbent assay. Splenocytes obtained from mice immunized with recombinant SV40 T-Ag did not lyse syngeneic tumor cells, indicating that no cytotoxic T lymphocyte response was induced. Control mice developed extensive lung metastasis and succumbed to lethal tumor within 4 weeks after challenge. These data indicate that immunization with the recombinant SV40␣T-Ag induces protective, T-Ag-specific immunity in an experimental pulmonary tumor metastasis model. Received: 20 August 1998 / Accepted: 25 November 1998     

Immune responses during human Schistosoma mansoni. XVII. Recognition by monoclonal anti-idiotypic antibodies of several idiotopes on a monoclonal anti-soluble schistosomal egg antigen antibody and anti-soluble schistosomal egg antigen antibodies from patients with different clinical forms of infection

A monoclonal human anti-soluble schistosomal egg Ag(SEA) antibody (E5) that stimulates anti-Id T cells and is idiotypically represented in pools of immunoaffinity-purified human anti-SEA antibodies from chronic, generally asymptomatic, intestinal (INT) patients (AM1 and AM5) was used to raise several monoclonal anti-Id: 1C2, 1C6, 4A8, 4F9, and 2A7. Cross-inhibition between these anti-Id identified distinct idiotopes on E5. Anti-SEA preparations from schistosomiasis patients (AM1, AM5, and others) were tested for their inhibition of the E5/monoclonal anti-Id reactions, in competitive ELISA. In either the E5/4A8 or E5/1C6 ELISA system, anti-SEA from INT (AM1 or AM5) or hepatointestinal (HI) (AM7) patients were able to inhibit these reactions. However, anti-SEA antibodies from acute (AM9) or hepatosplenic (HS) (AM3 or AM8) patients did not express Id that were inhibitory in these systems. These results suggest that a relatively high proportion of INT and HI anti-SEA antibodies express a dominant cross-reactive idiotope (CRI) recognized by 1C6/4A8. This CRI is also easily detected in plasmas from individual INT patients. Anti-Id 1C2 reacted strongly with an Id in AM1, AM5, or AM7, but one which also occurred, to a lesser extent, in AM3, AM8, and AM9. Monoclonal anti-Id 4F9 and 2A7 reacted weakly with idiotopes expressed by antibodies from all patients, regardless of the clinical form of their infection. These observations indicate that anti-SEA antibodies from INT and HI, but not acute or HS patients express dominant, CRI that are identified by 1C6, 4A8, or 1C2 and are also expressed on the INT-derived anti-SEA mAb E5.     

Idiotypic analysis of anti-I-Ak monoclonal antibodies. III. T- and B-cell responses to anti-Ia idiotopes are not modulated by syngeneic anti-idiotypic monoclonal antibodies

To investigate whether anti-idiotypic (anti-Id) antibodies activate T cells either directly or indirectly, we examined the ability of syngeneic anti-Id monoclonal antibodies (mAbs) to regulate idiotype (Id) expression, antigen-binding antibody production, and T-cell reactivity to antigen. Our idiotypic system consists of an anti-I-A mAb that carries an infrequently expressed Id. Using three syngeneic anti-Id mAbs (Ab2), we previously defined the idiotype of the 11-5.2.1.9 (11-5) anti-I-Ak mAb. Two of these mAbs, IIID1 and IA2, recognize the same or closely related epitopes on 11-5 and cross react with two additional anti-I-Ak mAbs, 8B and 39J; the third anti-Id mAb, VC6, recognizes a distinct epitope shared by 11-5 and 8B. In the present study, BALB/c (H-2d) mice were primed with varying doses of these anti-Ids and were then boosted with C3H (H-2k) spleen cells. Among 130 such primed mice, the syngeneic anti-Ids when tested at priming doses between 10 ng and 10 micrograms were unable to induce Id production. The priming anti-Id mAbs persisted in the serum of the mice and were detectable as late as 40 days after priming. Ab1 expression was not modulated in BALB/c mice immunized with KLH-coupled Ab2, however, this immunization elicited the production of Ab3 which shared idiotypes with 11-5, 8B, and 39J. BALB/c anti-C3H alloreactive T-cell clones were also not induced by anti-Id priming, nor could they be shown to bind directly to the three Ab2 used. Nevertheless, the proliferative response of one anti-I-Ak specific T-cell clone that recognizes the same epitope as 11-5, 8B, and 39J, was inhibited by the IIID1 and IA2 Ab2. Thus, a T cell can express an idiotype shared by a B cell, but the linked recognition of an Id-associated carrier determinant(s) by an alloreactive T cell is required to elicit an anti-Id antibody response. These results favor the possibility that the activation of T cells is not dependent upon their ability to bind to anti-Id, but rather on their capacity to respond to epitopes of Id-anti-Id antigen-antibody complexes formed on B cells.     

Detection of private and recurrent idiotopes on natural anti-tubulin antibodies by monoclonal anti-idiotopic antibodies

Two monoclonal anti-idiotopic antibodies (anti-Id) were raised in mice against a human monoclonal IgA,K displaying a monospecific anti-tubulin (anti-alpha- and anti-beta-tubulin) activity. One anti-Id (IgG,K) recognized a private idiotope, TID 3.2, present only on the IgA,K immunogen, close to or within the antigen-combining site. The other anti-Id (IgM,K) recognized a recurrent idiotope, TID 7.1, outside the paratope and present in normal human and BALB/c mouse serum, on 2 of 11 polyspecific human monoclonal immunoglobulins and on 6 of 11 murine natural monoclonal auto-antibodies exhibiting a widespread anticytoskeletal protein-binding activity. Both the idiotopes were absent on two induced anti-tubulin antibodies exhibiting a monospecific anti-alpha- and anti-beta-tubulin specificity. Utilizing competitive and additivity immunoassays, we could show that the polyspecific human and mouse anticytoskeletal antibodies tested, whether bearing the TID 7.1 Id or not, appeared to compete in variable degrees for epitopes on the tubulin molecule recognized by the monoclonal IgA,K but distinct from the epitopes recognized by the induced monospecific anti-tubulin antibodies. The high incidence of the recurrent TID 7.1 idiotope in man and mouse suggests an important physiologic and perhaps regulatory function of this idiotope. Furthermore our data suggest that a restricted family of germ-line genes, highly conserved during phylogeny, may encode for these idiotope-bearing Ig molecules.     

Monoclonal anti-idiotype induces protection against the cytotoxicity of the trichothecene mycotoxin T-2

An IgG1 mAb, designated HD11, specific for the trichothecene mycotoxin T-2 and capable of neutralizing its cytotoxicity was used to generate a syngeneic monoclonal anti-Id antibody. The generated anti-Id mAb, designated DE8, specifically bound to HD11 anti-T-2 mAb, and not to IgG1 mAb of irrelevant specificity or to normal mouse Ig. DE8 inhibited the binding of HD11 anti-T-2 to T-2-BSA-coated plates, whereas a control anti-Id mAb did not, suggesting recognition of an Id determinant associated with the T-2 binding site of HD11. Moreover, the binding of HD11 to DE8 and that of DE8 to HD11 were specifically inhibited by free T-2 mycotoxin. DE8 mAb was efficient in abrogating the protective effect of HD11 in the cytotoxicity of T-2 on the human epidermoid carcinoma cell line Hep-2. In vivo immunization of BALB/c mice with DE8 conjugated to KLH induced an anti-T-2 antibody titer comparable to that obtained with T-2-OVA immunization, whereas immunization with unconjugated DE8 resulted in a lower titered anti-T-2 response. Immunization with DE8-keyhole limpet or with unconjugated DE8 induced anti-T-2 antibody responses characterized by expression of "HD11-like" Id and by protection against T-2 cytotoxicity. However, the T-2-OVA-induced anti-T-2 response lacked the HD11+ Id and was only partially protective against T-2 cytotoxicity. This represents the first demonstration of the use of an anti-Id based vaccine in the in vivo induction of a protective antibody response against the cytotoxicity of a nonproteinaceous, small m.w. biologic toxin, whose very toxic nature precludes its use as the immunogen.     

V kappa gene usage, idiotype expression, and antigen binding among clones expressing the VHX24 gene family derived from naive and anti-idiotype immune BALB/c mice

The BALB/c myeloma protein ABPC48 binds beta(2-6)-linked fructosans and expresses genes derived from the VHX24 and V kappa 10 gene families. We have selected 30 hybridomas expressing the VHX24 gene family derived from mitogen-stimulated spleen cells of naive BALB/c mice and mice injected at birth with the syngeneic monoclonal anti-ABPC48Id, IDA10. The majority of mAb with kappa L chains uses V kappa 1. Antibodies reacting with IDA10 use both V kappa 10 and V kappa 1. Most of these VHX24+ mAb reacted with one or more members of a limited panel of predominantly polysaccharide Ag that have been previously observed to interact with antibodies expressing the VHX24 gene family. Nucleotide sequencing of selected VH and V kappa genes shows a very low frequency of somatic mutation. The effect of neonatal anti-Id injection on VHX24-V kappa pairing and Id expression is discussed.     

Anti-idiotypic antibody response to monoclonal anti-CD4 preparations in nonhuman primate species.

A series of mouse monoclonal anti-CD4 preparations was characterized for the ability to recognize overlapping epitopes on CD4 and to inhibit HIV/simian immunodeficiency virus (SIV) syncytium formation. Based on this characterization, mAb able to recognize CD4 epitopes overlapping the HIV binding site were selected and used to immunize nonhuman primates to elicit the production of specific anti-Id antibodies. Five baboons and five rhesus monkeys were immunized with either individual or a cocktail consisting of several monoclonal anti-CD4 preparations. All the nonhuman primates produced specific anti-Id that recognized either private or cross-reactive Id depending on the monoclonal anti-CD4 used to generate the anti-Id response. Inhibition assays were performed to ascertain the ability of: 1) soluble CD4 to inhibit the Id-anti-Id reaction and 2) the various anti-Id to inhibit the CD4-monoclonal anti-CD4 reaction. These studies demonstrated that some of the anti-Id recognized a cross-reactive Id that was associated with the Ag-combining site. In addition, some of the anti-Id weakly recognized SIV gp120 by Western blot analysis. These studies may be useful in designing experiments that may lead to a better understanding of the CD4-HIV gp120 interaction and to the production of Id and/or anti-Id reagents that might be used to manipulate this virus-receptor interaction.     

Expression of idiotype on the surface of human B cells producing anti-DNA antibody

We analyzed the idiotype (Id) expression on the surface of human anti-DNA antibody-producing cells. Murine monoclonal anti-Id antibodies with a specificity for determinants associated with the antigen-binding sites of human monoclonal anti-DNA autoantibodies were prepared. One anti-Id antibody reacted only with surface Id on anti-ssDNA-producing cells, but not with those on anti-dsDNA-producing B cell clones. Another anti-Id antibody did bind the surface Id on anti-dsDNA clones, but not those on anti-ssDNA clones. The interaction between anti-Id and surface Id was inhibited by pretreatment of the clones with DNA or appropriate polynucleotide antigens, or by preabsorption of anti-Id antibodies with free anti-DNA antibodies. Surface IgM and IgD expressed the same Id as the antibody secreted from the clones. The treatment of Id-positive clones by anti-Id antibody induced the redistribution of surface Id on the cells, indicating that these cells serve as targets for the regulatory action of anti-Id antibody.     

Evidence that anti-idiotype induced immunity to experimental African trypanosomiasis is genetically restricted and requires recognition of combining site-related idiotopes

The ability of anti-idiotypic (anti-Id) antibodies to immunize mice against African trypanosomiasis independent of antigen has been confirmed. Of three allogeneic anti-Id antibodies raised against three protective monoclonal antibodies, each with specificity for the variant surface antigen of a clone of Trypanosoma rhodesiense, only one (anti-7H11 Id) was effective in immunizing BALB/c mice against homologous challenge. The immunity was associated with the more rapid and enhanced expression of the corresponding Id after infection. The immunity was restricted to mice bearing genes linked to Igh-Ca, which appeared to control expression of this Id both in response to infection and anti-Id treatment. Another Id, 11D5, appeared to be under similar genetic control. Anti-11D5 Id, however, was ineffective in immunizing mice against infection despite inducing high levels of Id bearing molecules before challenge. The immunizing potential of the respective anti-Id antibodies appeared to be related to the relative concentrations of antibodies reactive with idiotopes near to or within the antigen-combining site, which, in turn, determined the relative proportion of Id-bearing clones activated that had antigen binding activity.     

Autoimmunity to DNA and nucleosomes in binary tetracycline-regulated polyomavirus T-Ag transgenic mice

The mechanism(s) responsible for autoimmunity to DNA and nucleosomes in SLE is largely unknown. We have demonstrated that nucleosome-polyomavirus T-Ag complexes, formed in context of productive polyomavirus infection, activate dsDNA-specific B cells and nucleosome-specific CD4(+) T cells. To investigate whether de novo expressed T-Ag is able to terminate nucleosome-specific T cell tolerance and to maintain anti-dsDNA Ab production in nonautoimmune mice, we developed two binary transgenic mouse variants in which expression of SV40 large T-Ag is controlled by tetracycline, MUP tTA/T-Ag (tet-off), and CMV rtTA/T-Ag (tet-on) mice. Data demonstrate that MUP tTA/T-Ag mice, but not CMV rtTA/T-Ag mice, are tightly controlling T-Ag expression. In MUP tTA/T-Ag transgenic mice, postnatal T-Ag expression activated CD8(+) T cells but not DNA-specific B cells, while immunization with T-Ag and nucleosome-T-Ag-complexes before T-Ag expression resulted in elevated and remarkably stable titers of anti-T-Ag and anti-dsDNA Abs and activation of T-Ag-specific CD4(+) T cells. Immunization of nonexpressing MUP tTA/T-Ag mice resulted in transient anti-T-Ag and anti-dsDNA Abs. This system reveals that a de novo expressed DNA-binding quasi-autoantigen maintain anti-dsDNA Abs and CD4(+) T cell activation once initiated by immunization, demonstrating direct impact of a single in vivo expressed molecule on sustained autoimmunity to DNA and nucleosomes.     

Properties of anti-idiotypic T cell lines propagated with syngeneic B lymphocytes. I. T cells bind intact idiotypes and discriminate between the somatic idiotypic variants in a manner similar to the anti-idiotopic antibodies

We describe the development of T cell lines possessing a binding specificity for syngeneic T15 idiotopes (Id) expressed on phosphorylcholine (PC)-reactive Ig. The lines were obtained by cultivation of BALB/c splenic T cells with T15 Id+ stimulator cells BCg3R-1d, a BALB/c lymphoma transfected with genomic sequences mu and kappa with S107 (T15) variable regions. Resulting Thyl-2+, L3T4+ cell lines depend on the T15 Id+ BCg3R-1d cells for growth and demonstrate the ability to bind TEPC15, a S107 germline-encoded, PC-specific Ig alpha. The specificity of the 125I-TEPC15 binding was studied in a competitive RIA with various unlabeled Ig. The isolated H and L chains of TEPC15 failed to inhibit the 125I-TEPC15 binding, and the T15-, PC-binding proteins M603 (alpha) and M511 (alpha) inhibited the binding either poorly or not at all. Moreover, the T cell lines had a discriminatory binding specificity for various T15+ Ig that are somatic variants of TEPC15 and that differ from each other in discrete, conformational Id (epitopes) detectable with specific monoclonal anti-Id. The T cell lines could be grouped according to their binding patterns, which were comparable to the recognition patterns of certain monoclonal anti-Id. These data suggest the existence of T cells with specificity for serologically-defined determinants of syngeneic idiotypes.     

Bispecific anti-idiotype/anti-CD3 antibody therapy of murine B cell lymphoma.

Retargeting of T cells by bispecific IgG which binds to both CD3 and a tumor-associated Ag can induce T cell lysis of target cells irrespective of TCR specificity. The current studies were designed to further explore the efficacy and specificity of bispecific IgG-directed therapy in an immunocompetent animal model, and to evaluate the mechanisms responsible for bispecific IgG-directed inhibition of tumor cell growth by using the 38C13 murine lymphoma system. In vitro, proliferation of activated T cells in the presence of bispecific IgG was increased when the relevant, but not the irrelevant target cells were present. Bispecific IgG specifically induced activated T cell mediated lysis of cells expressing the target Ag, but not of cells expressing an irrelevant Ag, even when the irrelevant cells were in the same cell mixture, indicating contact between target cells and T cells plays a major role in bispecific IgG-mediated lysis. Bispecific IgG was less effective than anti-Id at inducing target cell lysis when peritoneal macrophages were used as effectors, suggesting bispecific IgG Fc is not responsible for cytotoxicity in this system. In vivo, bispecific IgG was significantly superior to anti-Id, anti-CD3, or a combination of anti-Id and anti-CD3 in preventing tumor growth in immunocompetent mice inoculated with syngeneic lymphoma. Phenotypic evaluation of tumors that emerged despite therapy indicated bispecific IgG selects for the emergence of Id variant lymphoma cells. In separate studies, 38C13 tumor inocula containing cells recognized by the therapeutic antibody were supplemented with a small number of 38C13 cells which expressed a distinct Id not recognized by the therapeutic antibody. Untreated mice inoculated with this mixture developed tumors containing cells of both phenotypes, whereas tumors emerging from mice treated with bispecific IgG contained only cells expressing the nonreactive Id. These studies demonstrate bispecific IgG-directed lysis is therapeutically superior to monospecific anti-Id therapy in the 38C13 tumor model, and that tumor lysis is mediated largely by cell-cell contact. As with other forms of anti-Id based therapy, Id variants can emerge as resistant cell populations after bispecific IgG therapy.     

A public idiotypic determinant is present on spontaneous cationic IgG antibodies to DNA from mice of unrelated lupus-prone strains

A monoclonal anti-idiotypic antibody (anti-Id) to a public idiotype (Id) present on spontaneous IgG antibodies to DNA from NZB/NZW F1 mice recognized similar determinants on polyclonal and monoclonal IgG anti-DNA antibodies from mice of the unrelated MRL/lpr and BXSB strains. Incubation of the anti-Id with four of five monoclonal Id in solid phase inhibited their ability to bind DNA; however, different Id+ antibodies recognized different epitopes within the DNA molecule. Therefore, the public Id was located close to the antigen-binding regions but did not comprise all of those regions. Analysis of multiple polyclonal and monoclonal antibodies to DNA showed the Id on all subclasses of IgG. However, antibodies bearing the Id carried a neutral or cationic charge (10 of 10 monoclonals with pI greater than 7 were Id+); the presence of the Id on anionic IgG (pI less than or equal to 7) was infrequent (one of 21 serums, one of eight monoclonal antibodies). Therefore, IgG autoantibodies to DNA are constructed from closely related public idiotypes in several mouse strains that spontaneously develop lupus, and that Id is restricted to antibodies with a pI of 7 or greater.     

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.     

Immune responses during human schistosomiasis mansoni. XVI. Idiotypic differences in antibody preparations from patients with different clinical forms of infection

Antibodies were purified from pooled sera from patients with different clinical forms of schistosomiasis mansoni on immunoaffinity columns of schistosome soluble egg Ag (SEA). As previously reported, T lymphocytes in PBMC preparations from schistosomiasis patients (but not control subjects who have never been infected) proliferate when cultured in the presence of certain of these anti-SEA purified antibodies. We now show that PBMC from most patients with chronic schistosomiasis, regardless of the clinical form of their infection, respond to anti-SEA antibodies from sera of asymptomatic (intestinal) or hepatointestinal patients. In stark contrast, none responds to anti-SEA antibodies purified from sera of acute or hepatosplenic patients. All of these multiclonal anti-SEA antibody preparations were active in anti-SEA ELISA assays and gave comparable patterns of reactivity with SEA upon immunoblotting analysis. Immunization of rabbits with some of these anti-SEA antibody preparations, followed by absorption of the rabbit antisera on absorbents of normal Ig, produced specific anti-Id reagents. Use of these reagents in competitive ELISA systems demonstrated that the Id in stimulatory and nonstimulatory anti-SEA antibody preparations differ with regard to the proportion of the serologically defined Id expressed by each. It appears possible to screen patients' plasmas for the presence of shared Id by use of suitable Id/anti-Id competitive ELISA assays. Taken together these data indicate that only certain Id-positive preparations are stimulatory to patients' PBMC, and the expression of these T cell stimulatory, immunoregulatory Id on anti-SEA antibodies correlates with the clinical form of a patient's infection.