Idiotypic manipulation in mice: BALB/c mice can express the crossreactive idiotype of A/J mice

Maternal immunization modulates the primary immune response to 2-phenyl-oxazolone in BALB/c mice

The development of the antibody repertoire in newborn mice is greatly influenced by idiotype network interactions. It has been demonstrated that anti-idiotypic antibodies either directly injected or transferred from the mother may alter the repertoire for life. For an elucidation of the underlying mechanisms we have analyzed the primary immune response to 2-phenyl-5-oxazolone (phOx) coupled to chicken serum albumin (CSA) in BALB/c mice after complete disappearance of maternal antibodies which originated from different stages of affinity maturation. Depending on the serum titers of the mothers after primary (1 degree mo), secondary (2 degrees mo) or tertiary (3 degrees mo) immunization, maternal anti-phOx IgG persisted in F1 mice for up to 9 months. In addition, F1 mice born to 2 degrees mo developed--even without immunization--an anti-phOx IgM titer which reached levels similar to an antigen-induced primary response. An enhancement of the early primary anti-phOx as well as anti-CSA response was seen in F1 mice born from 1 degree mo, whereas the response was delayed when born to 2 degrees mo and 3 degrees mo. The antibody titers in the latter group of mice remained at a lower level for 3 months. In contrast, mice of the F2 generation which received a smaller amount of the same collection of maternal antibodies as F1 mice from 3 degrees mo exhibited a quite different primary response: (i) They showed an earlier onset in their anti-CSA response. (ii) Whereas normally a plateau in antibody titer was reached by the 4th weak after immunization, in 55% of the F2 mice a prolonged increase of the anti-phOx and anti-CSA antibody titers was observed. At 12 weeks after antigenic challenge, titers reached plateau levels of 6 x 10(5) which were never before seen in a primary phOx or CSA response. Thus, depending on its own immunological experience, the maternal immune system induces a state of memory in the offspring which results in a faster and/or enhanced immune response in the F1 and F2 [corrected] generations.

An idiotypic replica of carcinoembryonic antigen inducing cellular and humoral responses directed against human colorectal tumours

A monoclonal anti-idiotypic antibody (anti-Id MAb) 708 (IgG2b), which inhibited the binding of NCRC23 (IgG1) MAb to CEA and prevented radiolabelled CEA from binding to MAb NCRC23, was produced. No recognition of 3 other anti-CEA antibodies, 3 other IgG1 or 2 IgM MAbs was observed with this anti-idiotypic antibody. When an immunoblotting technique was used, 708 anti-Id MAb failed to bind to isolated heavy or light chains of MAb NCRC23, whereas binding was observed with intact antibody. Mouse, rat and human lymphocytes (in vitro) were immunized with 708 anti-Id MAb and the resultant Ab3 antibodies all inhibited binding of labelled 708 anti-Id MAb to MAb NCRC23 and also reacted with CEA, showing that 708 anti-Id MAb induced anti-CEA antibody responses. Similarly, mice immunized with 708 anti-Id MAb could be restimulated in vitro with either CEA or tumour cells expressing CEA which induced specific T-cell proliferative responses. Human tumour-infiltrating lymphocytes isolated from colorectal tumours or peripheral blood T cells from cancer patients were stimulated in vitro with 708 anti-Id MAb or an irrelevant IgG2b antibody. Six days later both sets of lymphocytes were restimulated with CEA, and lymphocytes primed to 708 anti-Id MAb proliferated in response to CEA. These results suggest that 708 anti-Id MAb can act as an idiotypic replica of CEA and stimulate cellular and humoral anti-CEA immune responses. It is therefore of great interest as an idiotypic vaccine against colorectal cancer.

A private idiotype can become recurrent through genetic recombination and gene(s) unlinked to the Igh locus governs its expression

Any immune response is characterized by its idiotypic profile. Two different kinds of idiotype (Id) have been described. Private Id are restricted to a few individuals from a species while recurrent Id appear in a large majority of individuals from the same species immunized with the same antigen. We describe, in this report, an experimental model whereby a private Id can become recurrent through genetic recombination. The immune response of A mice against the hapten arsonate is characterized by a recurrent Id called cross-reactive idiotype A (CRIA). A strongly CRI, called CRIA-like, can be occasionally detected in some BALB/c mice (5% to 10%) immunized with arsonate. Molecular studies show that CRIA and CRIA-like antibodies have highly homologous D segments and identical light chains. By contrast, their VH segments are vastly dissimilar. We have examined the anti-arsonate response of inbred strains of mice whose Igh loci are recombinant between those of A/He and BALB/c. Interestingly, we have observed that the CRIA-like Id which is private in BALB/c becomes recurrent in the AXC-1 strain which harbors the VH genes from BALB/c, the DH and CH genes from A/He. Structural studies demonstrate that highly homologous, VH, VL and D segments are used in BALB/c and AXC-1 mice. The basis for this differential expression of highly similar genes could be linked to the DH locus. However, F1 mice stemming from the cross between AXC-1 and BALB/c do not express the Id. The backcross analysis shows that the non-expression of the Id in F1 mice depends on genes unlinked to the Igh locus.

Structural characterization of antiidiotypic antibodies. Evidence that Ab2s are derived from the germline differently than Ab1s

We have found that syngeneic Ab2s in the antiarsonate system are serologically and structurally similar to one another. In contrast, the allogeneic Ab2 response is heterogeneous and derives from a large number of unrelated germline gene segments. The Ab2 response of the BALB/c strain to polyclonal A/J Ars A molecules can probably best be compared with a response to a foreign protein and might have been predicted in a strain that completely lacks the H chain V region gene from which the Ab1 derives. Partial variable region sequences of Ab2s from three other systems in addition to previously reported Ab2 structures indicates that this difference in allogeneic vs. syngeneic Ab2s may be a general phenomena. These data support Jerne's hypothesis of complementary V region genes existing in the germline. However, there is good evidence that these antiidiotypic antibodies are not derived directly from the germline, as somatic processes most likely play an important role in their generation. The D segments of Ab2s in the arsonate system as well as in other systems, are novel in structure and cannot easily be explained by previously described germline D segments. D-D fusion may play a role in the generation of the third hypervariable region in these antibodies.

Xenogeneic antibodies and atopic disease

Xenogeneic antibodies can survive food processing procedures with their biological activity intact and even enhanced. These antibodies can be absorbed from the human gut, and will function both as antigens and antibodies in the human immune system. Antibodies to bovine gamma globulins (BGG) have been detected in human sera and the family of anti-BGG antibodies must include anti-idiotypic antibodies, very low doses of which can influence the immune response. The hypothesis is that the human immune system may be primed by low-level exposure to xenogeneic antibodies specific for those human allergens which are ubiquitous in the farm environment, such as pollens, mites, and moulds, the result being a deleterious and inappropriate response on subsequent exposure to these allergens. Dairy products are the most important source of xenogeneic antibodies in the western diet, and the hypothesis may partly explain the association between cow's milk and allergies to substances other than milk proteins.

Human immune response to allergens of house dust mite, Dermatophagoides pteronyssinus. III. Cross-reactivity of bystander idiotopes on allergen-specific IgE antibodies

Rabbits were inoculated with affinity-purified human antibodies to the common house dust mite Dermatophagoides pteronyssinus (DPT) to produce anti-idiotypic (Id) antibodies. The Id carried by human IgE antibodies were studied in a radioimmunoassay in which specific anti-DPT IgE were first insolubilized on rabbit F(ab')2 fragments against human Fc epsilon. In a single individual specific anti-DPT IgE antibodies shared bystander idiotopes (i.e. idiotopes located outside the antigen-binding site) with IgG antibodies of the same specificity, since the adsorption on insolubilized anti-DPT IgG almost completely eliminated the binding of anti-Id antibodies to IgE. This differed from our previous observations (J.-M. R. Saint-Remy et al., Eur. J. Immunol. 1986. 16: 575) wherein distinct paratope-associated idiotopes were identified on IgG and IgE anti-DPT antibodies. The frequency of cross-reactions between idiotopes of anti-DPT IgE antibodies observed in ten unrelated individuals was less than 10% for bystander idiotopes. This finding confirmed the private character of the above idiotopes that we found earlier on anti-DPT IgG antibodies. However, one anti-Id antibody preparation was found to react with bystander idiotopes of anti-DPT IgE of most individuals, thereby suggesting the existence of a recurrent idiotope. The low frequency of inter-individual bystander idiotope cross-reactivity contrasted with the public character of paratope-associated idiotopes.

Identity of the V kappa 10-Ars-A gene segments of the A/J and BALB/c strains

To characterize the light chain gene segments involved in the murine immune response to keyhole limpet hemocyanin p-azophenylarsonate (Ars), we have determined the amino acid and/or nucleotide sequences of several anti-arsonate antibodies of the Ars-A family in the A/J, C.AL-20, and BALB/c strains. These structures have been compared to certain BALB/c anti-phenyloxazolone and anti-levan antibodies previously sequenced and to the A/J V kappa 10-Ars-A genomic sequence (where V kappa = kappa chain variable). These primary structural studies were complemented by Southern filter hybridization analyses utilizing V kappa and kappa chain joining (J kappa) molecular probes. We found a surprising uniformity of structure among these antibody light chains derived from different murine strains. Thus, in contrast to the heavy chain variable (Vh) regions of the Ars-A antibody family where the BALB/c strain lacks the VH gene segment utilized in the A/J Ars-A response, the light chain variable region gene segments at the V kappa 10-Ars-A locus appear to be identical between the two strains.

Idiotype-anti-idiotype interactions of VHIX-coded anti-progesterone and anti-arsonate antibodies. Comparison of passive haemagglutination and radioimmunoassays

The reactivity and specificity of polyclonal and monoclonal anti-idiotypic antibodies raised against monoclonal anti-progesterone and anti-arsonate antibodies have been studied by solid phase radioimmunoassay (RIA) with immobilized idiotype and by passive haemagglutination with idiotype-coupled red cells. The sensitivity of the two methods was comparable, though some cross-reactions were only detected by RIA. Passive haemagglutination was found to be especially suitable in screening for monoclonal anti-idiotypes in hybridoma supernatants and ascites, and had advantages over RIA in detection of syngeneic anti-idiotypes. Demonstration of binding site-associated idiotopes was possible by haemagglutination inhibition. RIA and haemagglutination were used to investigate the idiotypic relationships between BALB/c antiprogesterone and anti-arsonate monoclonal antibodies which share heavy chains encoded by VHIX variable region genes.

Idiotypic games within the immune network

In this paper, we have considered the problem of selection of available repertoires. With Ab2 as immunogens, we have used the idiotypic cascade to explore potential repertoires. Our results suggest that potential idiotypic repertoires are more or less the same within a species or between different species. A given idiotype "à la Oudin" can become a recurrent one within the same outbred species or within different species. Similarly, an intrastrain crossreactive idiotype can be induced in other strains, even though there is a genetic disparity between these strains. The structural basis of this phenomenon has been explored. We next examined results showing the loss and gain of recurrent idiotypes without any intentional idiotypic manipulation. A recurrent idiotype can be lost in a syngeneic transfer and a private one can become recurrent by changing the genetic background. The change of available idiotypic repertoires at the B cell level has profound influences on the idiotypic repertoires of suppressor T cells. All these results imply that idiotypic games are played by the immune system itself, a strong suggestion that the immune system is a functional idiotypic network.

Enhancement of antibody response by mouse dendritic cells pulsed with tobacco mosaic virus or with rabbit antiidiotypic antibodies raised against a private rabbit idiotype

The role of splenic lymphoid dendritic cells (DC) and macrophages (M phi) from mice in induction of immune responses in vivo has been investigated. Varying numbers of purified DC and M phi pulsed in vitro with tobacco mosaic virus (TMV) or with rabbit antiidiotypic antibodies (Ab2) directed against a private rabbit anti-TMV idiotype were injected back into syngeneic mice. In both systems, DC appeared to strongly enhance the primary and secondary responses to the virus. Optimal responses were obtained with 5 X 10(4) purified DC carrying TMV or rabbit Ab2. In contrast, M phi were less efficient by a factor of at least 100. These results show the potency of lymphoid DC as inducing cells in T-dependent antibody responses in vivo.

Induction by monoclonal anti-idiotypic antibodies of an anti-poly(Glu60 Ala30 Tyr10) (GAT) immune response in GAT-responder and GAT-nonresponder mice

Two different monoclonal anti-idiotypic (Id) antibodies, HP-Id20 and HP-Id22, recognizing two discrete idiotopes characteristic of the anti-poly(Glu60 Ala30 Tyr10) (GAT) response were used to immunize BALB/c (GAT-responder) and DBA/1 (GAT-nonresponder) mice. The monoclonals were injected either copolymerized with keyhole limpet haemocyanin or polymerized with glutaraldehyde. The specific response was studied by two assays: (a) inhibition of binding of monoclonal anti-GAT antibody G5Bb2-2 to HP-Id20 and HP-Id22 and (b) GAT binding assays. In BALB/c GAT-responder mice, HP-Id20 and HP-Id22 immunization led to the preferential stimulation of immunoglobulin idiotypically related to anti-GAT antibodies (Ab1') and expressing anti-GAT activity. The results obtained with BALB/c nu/nu mice indicated that this response is T-cell-dependent. By means of the same experimental protocol GAT-nonresponder animals could be induced to produce anti-GAT antibodies after HP-Id immunization. This last result indicates that anti-Id immunization can bypass Ir gene control and does not preferentially stimulate the induction of GAT-specific T suppressor cells.

Anti-DNA autoantibody activity and idiotypic relationships of human monoclonal proteins

Previous studies showed that polyclonal anti-DNA antibodies from patients with systemic lupus erythematosus (SLE) share cross-reactive idiotypes (CRI). In this report, we used human myeloma proteins (HMP), isolated from the serum of patients with multiple myeloma or Waldenström macroglobulinemia, as probes to further explore this idiotypic cross-reactivity. Fourty-four HMP were tested for DNA-binding capacity and for expression of CRI associated with lupus anti-DNA antibodies. Anti-DNA IgG were immunoaffinity purified from the serum of patient TOF with severe SLE. A xenogeneic anti-idiotype antibody to this IgG was raised in rabbit. This anti-idiotype recognized CRI associated with the combining site of anti-DNA IgG from unrelated SLE patients. Using inhibition competitive-immunoassays, we found that these CRI were present on all but one of the DNA-binding HMP. Furthermore, we observed that these CRI were detectable on an IgG2 lambda, a HMP devoid of anti-DNA activity. These findings are in agreement with those previously obtained in similar studies using murine monoclonal anti-DNA antibodies. These converging results suggest that antibodies expressing anti-DNA-related CRI and antibodies exhibiting anti-DNA-binding affinity constitute overlapping molecular subpopulations.

Induction of anti-tobacco mosaic virus antibodies in mice by rabbit antiidiotypic antibodies

Conventional rabbit antiidiotypic antibodies were raised against a private rabbit anti-tobacco mosaic virus (TMV) idiotype. These rabbit antiidiotypic antibodies were covalently coupled to lipopolysaccharide and then injected into BALB/c mice. As compared with controls, these mice, which have never seen the antigen, synthesized anti-TMV antibodies that are strongly idiotypically cross-reactive with the starting rabbit idiotype. Monoclonal anti-TMV antibodies were prepared from these mice. Furthermore, xenogeneic or syngeneic antiidiotypic antibodies, raised against these monoclonal anti-TMV antibodies, recognized specifically the rabbit idiotype. Rabbit antiidiotypic antibodies alone can induce the same effects, but the concentration of anti-TMV antibodies is lower.

Complete amino acid sequence of heavy chain variable regions derived from two monoclonal anti-p-azophenylarsonate antibodies of BALB/c mice expressing the major cross-reactive idiotype of the A/J strain

The primary structure of A/J anti-p-azophenylarsonate (anti-Ars) antibodies expressing the major A-strain cross-reactive idiotype (CRIA) has provided important insights into issues of antibody diversity and the molecular basis of idiotypy in this important model system. Until recently, this idiotype was thought to be rarely, if ever, expressed in BALB/c mice. Indeed, it has been reported that BALB/c mice lack the heavy chain variable segment (VH) gene that is utilized by the entire family of anti-Ars antibodies expressing the A/J CRI. Recently, however, it has been possible to elicit CRIA+, Ars binding antibodies in the BALB/c strain by immunizing first with anti-CRI and then with antigen. Such BALB/c, CRIA+ anti-Ars antibodies can be induced occasionally with antigen alone. VH region amino acid sequences are described for two CRIA+ hybridoma products derived from BALB/c mice. While remarkably similar to each other, their VH segments (1-98) differ from the VH segments of A/J CRIA+, anti-Ars antibodies in over 40 positions. Rather than the usual JH2 gene segment used by most A/J CRIA+ anti-Ars antibodies, one BALB/c CRIA+ hybridoma utilizes a JH1 gene segment, while the other uses a JH4. However, the D segments of both of the BALB/c antibodies are remarkably homologous to the D segments of several A/J CRIA+ antibodies sequenced previously, as are the amino terminal amino acid sequences of their light chains. These data imply that BALB/c mice express the A/J CRIA by producing antibodies with very similar, if not identical, light chain and heavy chain D segments, but in the context of different VH and JH gene segments than their A/J counterparts. The results document that molecules that share serologic specificities can have vastly different primary structures.

Idiotypic analysis of potential and available repertoires in the arsonate system

We have shown that, by suitable idiotypic manipulation, BALB/c mice can express the major cross-reactive idiotype (CRI) of A/J mice in response to azophenylarsonate (Ars). In order to know if the CRIA idiotype is present in the potential repertoire of BALB/c before any intentional selection, we used polyclonal activation in vitro and limiting dilution analysis. The readout was done with two monoclonal anti-CRIA antibodies that recognize distinct idiotopes on a CRIA+ A/J germline-encoded monoclonal antibody. We studied the frequency of CRIA+ lipopolysaccharide (LPS)-reactive cells in the spleens of nonimmune and immune A/J mice and in the spleens of naive and manipulated (i.e., producing CRIA+ antibodies) BALB/c mice. A/J and BALB/c naive individuals presented very high frequencies of Ars-specific B cells while the frequency of CRIA+ B cells was only a minor subset (0.5%) of the total Ars-specific subset in the two strains. When A/J mice were immunized with Ars-keyhole limpet hemocyanin, a clear preferential expansion of the CRIA+ minor subset of A/J mice was observed (100x). No such enhancement was observed in BALB/c mice similarly treated. Manipulated BALB/c mice presented a higher frequency of CRIA+ anti-Ars B cells than naive or antigen-immunized BALB/c individuals.

Anti-hypervariable region antibody induced by a defined peptide: an approach for studying the structural correlates of idiotypes

The structural correlates of idiotypes have been sought in several antibody systems. However, the precise molecular basis of idiotypes are exceedingly difficult to define. Antibodies of predetermined specificity can be induced by immunization with synthetic peptides. In the present experiments, a synthetic peptide corresponding to a hypervariable region on a monoclonal human IgM rheumatoid factor (Sie) has been used to induce specific anti-hypervariable region antibodies. The antibodies bound to the intact Ig molecule and to its isolated heavy chains but not to other IgM paraproteins nor to pooled human IgG. The binding of the antibody to the intact IgM was inhibited specifically by the free peptide, and the antibody activity was removed by a peptide-coupled affinity column. These results clearly demonstrate that specific anti-idiotypic antibody of predefined specificity can be induced by a hypervariable region peptide. Antibodies of this class may provide a new tool for defining the structural correlates of idiotypes.