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.     

In vitro manipulation of human anti-DNA antibody production by anti-idiotypic antibodies conjugated with neocarzinostatin

Anti-DNA Id, 0-81, consist of 5 to 51% of Id in human anti-ssDNA antibodies; NE-1-Id shares 2 to 20% of those in anti-dsDNA antibodies. Thus, both 0-81-Id and NE-1-Id are of the cross-reactive Id that are commonly present among anti-DNA antibodies. In order to manipulate the production of anti-DNA antibodies by human PBL, we used mouse antiidiotypic mAb or those conjugated with a cytotoxic agent, neocarzinostatin. Treatment with the conjugates caused profound suppression of anti-ssDNA and anti-dsDNA antibody synthesis related to 0-81- and NE-1-Id. This was attributed to the specific killing of the clones bearing anti-DNA Id among the lymphocytes, evidenced by the indirect rosette formation tests. The Id-mediated suppression was not solely due to selective elimination of Id-positive B cells, because 50 to 92% of anti-DNA antibodies were suppressed by treatment with the conjugates. This was supported by flow cytometry analysis that showed a decrease of anti-Id-reactive cells when T cells were treated with the conjugates. This method, then, will permit an analysis of the question as to whether T cells reactive to anti-idiotypic antibodies might participate in the regulatory mechanism for anti-DNA production and, in addition, may lead to a new therapy for SLE.     

Induction of allergen-specific IgE and IgG responses by anti-idiotypic antibodies

In order to explore idiotypic, anti-idiotypic, and anti-anti-idiotypic responses to allergens, BALB/c mice were immunized with affinity-purified human idiotypic antibodies directed against a highly purified shrimp allergen. This resulted in the production of anti-idiotypic antibodies which were quantitated by using rabbit idiotypic antibodies raised against the same purified allergen. The mouse anti-idiotypic antibodies recognized shrimp-specific human idiotypic antibodies of the IgE isotype from 18 of 20 individuals, and IgG antibodies from 14 of 20 shrimp-sensitive patients. Immunization of BALB/c mice with affinity-purified, allergen-specific anti-idiotypic antibodies induced anti-allergen IgE and IgG responses in the absence of the allergen. This paper thus presents evidence that anti-idiotypic antibodies raised against allergen-specific idiotypic antibodies may substitute for the original allergen in the induction of allergen-specific idiotypic antibodies. The demonstration of shared idiotopes on IgG and IgE antibodies in the sera of shrimp-sensitive patients supports the use of allergen-specific anti-idiotypic antibodies as surrogate allergens.     

Idiotypic determinants of monoclonal antibodies that bind to 3-fucosyllactosamine

Many monoclonal antibodies that react with the lacto-N-fucopentaose III (LNF III) antigenic determinant, Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc, have been described recently. The terminal trisaccharide of this determinant, fucosyllactosamine, is present on glycolipids and glycoproteins and on the surface of granulocytes, monocytes, and other cells. To study the structural and genetic diversity of these antibodies, syngeneic anti-idiotypic monoclonal antibodies were produced in BALB/c mice against PMN 6, a monoclonal antibody directed against this sequence. Anti-idiotypic antibodies 6B1 and 6C4 reacted with 50% of a panel of 20 anti-LNF III monoclonal antibodies, whereas 6A3 reacted strongly only with PMN 6. This indicates that the determinants recognized by 6C4 and 6B1 represent major cross-reactive idiotopes of this family of antibodies. The binding of idiotypic antibodies to a glycolipid bearing this antigenic determinant was completely inhibited by the three anti-idiotypic antibodies, 6A3, 6B1, and 6C4. The idiotopes could be demonstrated on the heavy chain of the monoclonal antibodies by an antibody transfer technique when mild reducing conditions were employed, but a high concentration of reducing agent destroyed the idiotypic determinants. This suggests that the anti-idiotypic antibodies recognize conformational structures expressed on the heavy chain molecules. The binding of 18 monoclonal antibodies to two glycolipid antigens and to a fucosyllactosamine-bovine serum albumin conjugate was compared. Antibodies that possessed the 6C4 cross-reactive idiotope bound to fucosyllactosamine-bovine serum albumin more weakly than idiotype-negative antibodies (p = 0.001). This suggests that the 6C4-positive antibodies might represent germline structures.     

Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human schistosomiasis. II. In vitro granuloma modulation induced by polyclonal idiotypic antibodies

We have previously reported on Id/anti-Id-receptor interactions in clinical human schistosomiasis. These findings support a hypothesis that anti-SEA cross-reactive Id develop in some patients during the course of a chronic infection and participate in regulation of anti-SEA cellular immune responses. We report here on experiments that extend those observations to the regulation of granulomatous hypersensitivity measured by an in vitro granuloma model. T cells from chronic intestinal schistosomiasis patients were stimulated in vitro with anti-SEA Id and assayed in an autologous in vitro granuloma assay for modulation of granuloma formation. These anti-SEA Id-reactive T cells were capable of regulating autologous in vitro granuloma formation. Both CD4 and CD8 T cells could be activated to regulate granuloma formation. This regulatory activity, initiated with stimulatory anti-SEA idiotypic antibodies, was antigenically specific and was dependent on the presence of intact F(ab')2 Ig molecules. The ability to elicit this regulatory activity appears to be dose dependent and is more easily demonstrated in chronically infected intestinal patients or SEA-sensitized individuals. These data support the hypothesis that anti-SEA cross-reactive Id are important in regulating granulomatous hypersensitivity in chronic intestinal schistosomiasis patients and these cross-reactive Id appear to play a major role in cell-cell interactions that result in the regulation of anti-SEA cellular immune responses.     

A cross-reactive idiotype, QUPC52 IdX, present on most but not all anti-alpha (1 replaced by 6) dextran-specific IgM and IgA hybridoma antibodies with combining sites of different sizes

Seven BALB/c IgM, 4 BALB/c IgA, and 1 C57BL/6 IgA anti-alpha (1 replaced by 6) dextran hybridoma antibodies were characterized idiotypically. Five of the 7 IgM and all 4 BALB/c IgA proteins bear a cross-reactive idiotype present on the anti-alpha (1 replaced by 6) dextran BALB/c myeloma protein QUPC52 and on a majority of anti-alpha (1 replaced by 6) dextran antibodies in BALB/c mice. Of these 9 monoclonal antibodies, some have combining sites as large as 6 glucose residues, and some have combining sites as large as 7 glucose residues. Individual idiotypes present on QUPC52 are differentially expressed on the 9 hybridoma proteins that bear the cross-reactive idiotype. One BALB/c IgM hybridoma protein and the C57BL/6 IgA hybridoma protein did not react with anti-QUPC52 idiotypic antibodies; another BALB/c IgM hybridoma antibody showed only marginal reactivity.     

The regulation of resistance to Schistosoma mansoni by auto-anti-idiotypic immunity. III. An analysis of effects on epitopic recognition, idiotypic expression, and anti-idiotypic reactivity at the clonal level.

Auto-anti-idiotypic mechanisms can regulate the protective immune response against Schistosoma mansoni. Anti-idiotypic responses were stimulated by immunization of mice either with nonspecifically induced lymphoblasts, produced with Con A, or with Ag-induced lymphoblasts bearing specific idiotypic receptors. The effect of the induced anti-idiotypic response upon clonotypic cellular reactivity was assessed in vitro through the suppression of antigen-mediated blast transformation by cloned T cells and in vivo by suppression of resistance to S. mansoni and delayed-type hypersensitivity responses against specific Ag. Differential regulation of humoral immune responses was studied at the levels of specific epitopic recognition, the expression of specific Id, and the production of anti-idiotypic responses directed against mAb bearing specific Id. Anti-idiotypic sensitization resulted in variable (10 to 90%) suppression of the immune response to discrete antigenic epitopes, the expression of specific idiotypic phenotypes, and anti-idiotypic, antiparatopic responses against T cell clonotypes and antibody idiotypic phenotypes. In vitro admixture and in vivo challenge studies resulted in consonant differential suppression. Thus idiotypic regulation can mold the fine specificities of the protective immune response to S. mansoni at the clonal level and may provide an approach to optimize the expression and assessment of resistance.     

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.     

Angiotensin II (AII)-related idiotypic network. III. Comparative analysis of idiotopes and paratopes borne by monoclonal antibodies raised against AII (AB1) and its internal image (AB3)

We have previously produced mAb against angiotensin II (AII), a phylogenetically conserved vasopressive octapeptide, and shown that they identify four distinct epitopes on the AII molecule. In addition we used internal image bearing polyclonal antiidiotypic antibodies raised against rabbit anti AII to produce mAb3. In this study we analyze the segregation of the idiotypic and paratopic repertoires of the mAb1 and mAb3. Analysis of mAb1 carried out with polyclonal Ab2 raised against the four distinct paratopes permitted classification of the mAb1 into four categories: (p+, id+) comprises antibodies with shared paratopic and idiotypic specificities: (p+, id-) is made up of antibodies that fail to express the Id defined by Ab2 raised against other antibodies pertaining to the same paratopic group; (p-, id+) includes antibodies that express cross-reactive Id on distinct paratopes; (p-, id-) refers to antibodies unrelated by their paratopes and Id mAb2 confirmed these results and showed expression of identical or closely related Id on clearly distinct paratopes. At the Ab3 level, using polyclonal Ab4, there was a higher degree of Id cross-reactivity between the two paratopes available. These data suggest that the parallel set concept may apply to the immune response to a natural peptidic Ag and its internal image. Comparison of idiotypic repertoires of mAb1 and mAb3 (using Ab2 and Ab4 antibodies) confirmed the lack of public Id and showed the predominance on mAb3 of "new" idiotypes absent from mAb1 molecules, as expected for internal image-induced antibodies. Cross-reactive idiotypes defined on mAb1 and conserved on mAb3 were expressed on the two paratopes defined at the Ab3 level. They were located on the H chain of the homologous paratope and required the association of H and L chains on the heterologous paratope. Our analysis suggests that, in the AII system, the idiotypic and paratopic repertoires segregate at least in part independently. The paratopic repertoire is limited to a small number of phylogenetically conserved specificities and may be encoded by germline genes. In contrast, the idiotypic repertoire is broader with respect to specificities, species, and localization on H and L chains. This extended diversity may be generated by somatic mutations or use of various combinations of H and L chains and/or V, D, J segments.     

The NZB X SWR model of lupus nephritis. I. Cross-reactive idiotypes of monoclonal anti-DNA antibodies in relation to antigenic specificity, charge, and allotype. Identification of interconnected idiotype families inherited from the normal SWR and the autoimmune NZB parents

The incidence of lupus nephritis is low in autoimmune NZB mice, but when they are crossed with normal SWR mice, almost 100% of the female F1 hybrids (SNF1) develop lethal glomerulonephritis. In a previous study we showed that anti-DNA auto-antibodies produced by the SNF1 mice were qualitatively different from those made by the NZB parents with respect to their isotype, charge, and antigenic specificity patterns. Here we studied idiotypic cross-reactions among the 65 monoclonal anti-DNA antibodies that were derived from four NZB and seven SNF1 mice. A library of 15 anti-idiotypic antibodies were prepared by immunizing rabbits with 15 monoclonal anti-DNA antibodies selected from the panel of 65. We identified 10 cross-reactive idiotype (CRI) families among this large collection of autoantibodies. Five of these CRI families were restricted to cationic anti-DNA antibodies that were exclusively of SNF1 origin, and the strongly cross-reacting members were predominantly IgG2b auto-antibodies with the allotype of the normal SWR parent. The cationic anti-DNA CRI families could be grouped into an interrelated cluster called the Id564 cluster. The other five anti-DNA CRI families were not restricted to any particular parental allotype or charge, although two of these CRI were shared exclusively by SNF1-derived autoantibodies and four of these CRI families could also be grouped into an idiotypically interrelated cluster called the Id512 cluster. In the case of seven out of the 10 CRI families, the idiotypic determinants detected were close to the antigen-binding site of the anti-DNA antibodies. The results indicate that the idiotypic repertoire of anti-DNA autoantibodies produced by the SNF1 mice is different from the NZB parents, and potentially pathogenic (cationic) antibodies produced by the SNF1 mice that are encoded by genes from the normal SWR parent can be identified as distinct CRI families. In the accompanying paper we demonstrate the role of these anti-DNA CRI families in the development of lupus nephritis.     

Selection of antibody repertoires by anti-idiotypes can occur at multiple steps of B cell differentiation

These experiments were designed to evaluate whether alterations in Id expression after anti-Id treatments result from direct modulation of Id-producing B cells, and whether idiotypic selection operates in bone marrow or spleen B cells. By using the NPb Id model, we have studied the functional behavior of isolated LPS-reactive B cells transferred from B6 mice into histocompatible LPS-NR B10.Cr hosts and primed with LPS conjugates of anti-Id antibodies. We have found that previous anti-idiotypic manipulation of host mice by neonatal administration of suppressive doses of Ac 38 antibodies, or adult injection of enhancing doses of Ac 146 antibodies, modulated the T cell-independent Id response of either immature bone marrow or mature splenic responding cells, transferred from normal, untreated donors. These results are interpreted to suggest that selection of antibody repertoires by anti-Id may occur at multiple steps of B cell differentiation.     

Idiotypy of anti-Rh antibodies

Anti-id sera to Rh antibodies were produced by injecting rabbits with purified Rh antibodies. These sera were shown to agglutinate O Rh+ RBC coated by the immunizing antibody and--in some cases--by other anti-D antibodies. Id and cross-reactive id were shown to be located in the antigen-binding and in the non-antigen binding regions of Rh antibodies. An unique example of evolution of idiotypic specificities on human antibodies has been reported. Lastly, we have demonstrated by rosette assay, presence on some PBL of receptors for Fab'2 anti-Rh coating O Rh+ red cells. Rosettes could not be obtained with lymphocytes of a donor and Fab'2 anti-Rh of another individual. Rosettes appeared at a period of time in which the amount of antibody was decreasing.     

Suppression of murine lupus nephritis by administration of an anti-idiotypic antibody to anti-DNA

The suppression of pathogenic antibodies to DNA in NZB/NZW f1 female mice was achieved by repeated inoculation of the mice with a monoclonal anti-idiotypic antibody (anti-Id). The anti-Id, an IgG1, kappa, was directed against a major cross-reactive idiotype (Id) on NZB/NZW IgG antibodies to DNA. One hundred micrograms of the anti-Id were inoculated i.p. every 2 wk, beginning at 6 wk of age (nondiseased mice--no circulating anti-DNA or proteinuria) or 20 wk of age (diseased mice--all with circulating anti-DNA, one-third with proteinuria). As controls, littermates received an IgG, kappa non-DNA-binding myeloma or no treatment. In the young mice, nephritis and anti-DNA antibodies appeared at the same time in all groups, and their circulating antibodies to DNA did not bear the target Id. In the older (20-wk-old) mice, survival was significantly prolonged because of delay in the onset of nephritis; the total quantities of antibodies to DNA were diminished, and the target Id, initially present on circulating IgG, was deleted. These benefits were transient; the suppression of antibodies was followed by the appearance of large quantities of anti-DNA that did not bear the major Id. Therefore, although administration of anti-Id was effective in reducing an undesirable antibody response after the target Id was present on circulating antibodies, the benefits were limited, probably by Id "switch" or by increased synthesis of pathogenic antibodies bearing a minor Id.     

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.     

A cross-reactive idiotype on anti-collagen antibodies in collagen-induced arthritis: identification and relevance to disease

Immunization of mice with type II collagen (CII) leads to the production of anti-CII antibodies and, in susceptible strains, to the induction of arthritis. Specifically purified anti-CII antibodies from arthritic DBA/1 mice were used to prepare a rabbit anti-idiotypic antiserum. This antiserum recognizes a cross-reactive idiotype (CRI) present on 20-25% of anti-CII antibodies from DBA/1 mice immunized with bovine CII. The CRI is not present on DBA/1 anti-trinitrophenyl, undetectable in normal Ig and not Igh allotype linked. The presence of this CRI was examined after antigen specific suppression of the anti-CII antibody response by intravenous administration of chick or bovine CII. While intravenous injection of bovine CII, prior to immunization with chick CII, greatly reduces both the incidence of arthritis and the anti-CII response, the fraction of anti-bovine CII which expresses the CRI is increased by this treatment. These findings suggest that the CRI characterizes a disease-unrelated fraction of anti-CII which recognizes bovine and chick CII, but probably not mouse CII. In addition, attempts at idiotypic regulation of arthritis incidence and antibody response by in vivo administration of anti-idiotypic serum also indicate that the CRI-bearing antibody is not important for the induction of arthritis.     

Analyses of Idiotypes on Anti-α-1, 6-Dextran Antibodies in Mice

When mice of strains C57BL/6, C3H/He, and BALB/c were immunized with native dextran B512, only a small amount of IgM antibody was produced, but a substantial amount of anti-dextran antibody of IgG class was produced after immunization with a conjugate of dextran T10 and keyhole limpet hemocyanin regardless of the mouse strain used. Isoelectric focusing (IEF) spectra revealed limited heterogeneity of anti-dextran antibody of IgG class with strict consistency in all individual sera from C57BL/6 mice, even after secondary immunization, whereas antibodies from C3H/He and BALB/c mice showed more heterogeneous IEF spectra with some individual variations. Rabbit anti-idiotypic (Id) antibodies were raised by immunization with a subfraction of anti-dextran antibody of IgG class from C57BL/6 mice, which showed major bands focused at around pH 7.7 upon IEF. It was found by using the anti-Id antibodies that virtually all anti-dextran antibody molecules of both IgG and IgM classes from C57BL/6 mice possessed common Id determinants which can be classified into two specificities, one specific for antibody from C57BL/6 mice and the other cross-reactive with antibodies from BALB/c and C3H/He mice. About 80% of the antibody molecules from BALB/c and less than 20% of those from C3H/He mice were positive for the interstrain cross-reactive Id. Both Id determinants seemed to be closely related to the antigen binding sites, or at least to reside in the vicinity of the antigen binding sites of anti-dextran antibody.     

Recognition of a B cell lymphoma by anti-idiotypic T cells

Idiotypic IgM derived from a B cell lymphoma can act as a tumor-associated Ag, in that immunization with this purified protein generates an anti-idiotypic immune response that specifically suppresses tumor development. Spleens of immune mice contain T cells that proliferate in response to idiotypic IgM. However, idiotypic Ag is presented to the T cells most efficiently in its natural form at the surface of the lymphoma cells, than as soluble IgM plus presenting cells. Variant tumors that display either little or no idiotypic IgM at the cell surface, but which are otherwise indistinguishable from parental tumor, induce a weak response or fail to stimulate the T cells, respectively. Anti-idiotypic lines and clones have been derived from the splenic T cells by growth in the presence of irradiated tumor cells. Phenotypic analysis revealed that cells from both lines and clones express CD3 and CD4 Ag, but not CD8. Recognition of tumor Id, which required no added presenting cells, was inhibited by antibody against MHC class II Ag, and variably by anti-CD4. Proliferative responses were inhibited by anti-idiotypic antibodies, but also by antibodies against the constant region of the mu H chain, indicating that perturbation of the surface IgM abrogates availability of idiotypic determinants to the T cells.     

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.     

A cross-reactive idiotype on anti-DNA antibodies defines a H chain determinant present almost exclusively on IgG antibodies

We have previously reported two anti-idiotypic antibodies, 3I and 8.12, that recognize L chain determinants on anti-DNA antibodies. We have generated a new anti-idiotypic antibody, F4, that recognizes a H chain determinant on cationic anti-DNA antibodies. F4 reactivity is present in high titer in serum of approximately 60% of SLE patients and on 84 of 706 myeloma proteins. It is preferentially associated with 3I reactive L chains. Furthermore, antibodies bearing both the F4 and 3I idiotypic determinants preferentially bind DNA. Amino acid sequencing of H chains isolated from four F4-reactive myeloma proteins suggests that they derive from two currently identified VH gene families. F4 reactivity is restricted almost exclusively to Ig of the IgG isotype suggesting that F4 may recognize either a somatically mutated hypervariable region or a variable region used late in the immune response. F4, therefore, represents a new idiotypic family preferentially associated with auto-Ag specificity and having features of an Ag-driven immune response.     

Idiotype vaccination against murine B cell lymphoma. Humoral and cellular requirements for the full expression of antitumor immunity

The roles of humoral and cellular antitumor immune responses induced by immunization with tumor-derived idiotypic IgM were studied in a syngeneic, transplantable B cell lymphoma (38C13) of C3H mice. Id vaccination with keyhole limpet hemocyanin-conjugated Id induced protection against a subsequent lethal tumor challenge. Such immunizations elicited anti-idiotypic antibodies that were cytotoxic in in vitro antibody-dependent cellular cytotoxicity assays as well as in vivo passive transfer experiments. L3T4+ T cells, which proliferated in vitro in response to the specific Id protein, were also induced. However, cells mediating direct cytotoxicity, either in vitro or in vivo, were not observed in the lymph nodes, spleens, or peritoneal cavity of immune mice or at the site of tumor regression as demonstrated by using a tumor sponge implantation model. In addition, in vitro sensitization of immune lymphocytes against 38C13 tumor cells failed to induce cytotoxicity. Immunization with lipid conjugated Id also elicited a T cell proliferative response but failed to induce anti-idiotypic antibodies and did not confer resistance to tumor growth. These results suggest that anti-idiotypic antibodies play the major role in the destruction of 38C13 tumor cells. However, in vivo depletion of L3T4+ or Lyt-2+ cells from 38C-Id-keyhole limpet hemocyanin-immunized mice resulted in diminished protection against a tumor challenge. Thus, although humoral responses appear to play the predominant part in tumor destruction, cellular responses are also required for the full expression of antitumor immunity in this system.