Cross-reactive Idiotype Research Articles

The lymphoid system in hepatitis C virus infection: autoimmunity, mixed cryoglobulinemia, and Overt B-cell malignancy.

Like other hepatotropic viruses, hepatitis C virus (HCV) shares the property of inducing hepatocellular damage, possibly through induction of immune mechanisms that lead to hepatocellular necrosis. After infection of hepatocytes, and possibly other cells, humoral and cellular responses occur aimed at prevention of virus dissemination and elimination of infected cells. The early activated mechanisms include production of nonspecific and specific antibodies that represent the first-line of defense against invading foreign pathogens. As a consequence, circulating immune complexes are promptly formed, and antigen uptake and processing by specialized cells are enhanced. A major fraction of circulating immunoglobulins (Igs) are part of the spectrum of the so-called natural antibodies, which include anti-idiotypic antibodies and molecules with rheumatoid factor (RF) activity. They mainly belong to the IgM class, are polyclonal, and have no intrinsic pathogenetic potential. In 20-30% of HCV-infected patients, RFs share characteristics of high affinity molecules, are monoclonal in nature, and result in the production of cold-precipitating immune complexes and mixed cryoglobulinemia. It has been shown that anti-idiotypic antibodies and polyclonal and monoclonal RF molecules have the same cross-reactive idiotype, called WA, suggesting that their production is highly restricted. This strongly indicates that they arise from stimulation with the same antigen, likely HCV. It has also been speculated that B-1 (CD5+) and B-2 (CD5-) B-cell subsets, which use a limited number of VH germline genes, underlie the production of low-affinity polyclonal and high-affinity monoclonal antibodies, respectively. The persistent production of monoclonal RF molecules implies the existence of a further mechanism capable of restricting the reactivity and reflects a distinct selection of a cell population that can be maintained throughout life because they are continuously exposed to antigen pressure. Either polyclonal or monoclonal profiles of B-cell expansion are demonstrable in the liver of most HCV-infected patients. The occurrence of B-cell clonal expansion is strictly related to intrahepatic production of RF molecules, and this suggests that liver is a microenvironment, other than lymphoid tissue, in which a germinal centerlike reaction is induced. The frequent detection of oligoclonal B-cell expansion may, indeed, represent a key pathobiologic feature that sustains nonmalignant B-cell lymphoproliferation. The preferential expansion of one clone would in turn lead to a monoclonal pattern that could favor stochastic oncogenic events. It can be postulated that HCV is the stimulus not only for the apparent benign lymphoproliferative process underlying a wide spectrum of clinical features, but also for the progression to frank lymphoid malignancy in a subgroup of patients. Current data indicate a higher prevalence of overt B-cell non-Hodgkin's lymphoma in HCV-infected patients, especially in some geographic areas.

Infection-stimulated or perinatally initiated idiotypic interactions can direct differential morbidity and mortality in schistosomiasis

In this and previous publications, we have described two areas of study that now converge, and that we propose provide insights into immunoregulatory processes that may develop during chronic endemic diseases and contribute to the balance and chronicity of the essential host/parasite relationship. The first area of study is that of idiotypic/antiidiotypic interactions within human and experimental immune systems during Schistosoma mansoni infections. The companion study concerns a naturally developing differential development of morbidily and mortality during chronic experimental schistosomiasis mansoni. Based on the data presented and reviewed, we propose that either by six weeks of infection, or through perinatal idiotypic manipulation, the immune system of the infected host is 'programmed' into responding either with regulatory cross-reactive idiotypes or not, and that this commitment differentially controls multiple subsequent immune responses and can determine the degree of consequent morbidity and mortality due to schistosomiasis.

Anti-Idiotypic Sera Against Monoclonal Anti-Porcine Growth Hormone Antibodies: Production in Rabbits and Characterization of Specificity

Antisera were raised in rabbits against two mouse monoclonal anti-porcine growth hormone (pGH) antibodies. Anti-idiotypic antibodies were isolated from rabbit sera by successive passage over immunoadsorbent columns of normal mouse 1g (mIg), followed by the specific immunizing monoclonal and elution from the latter. Enzyme linked immunoadsorbent assay (ELISA) for anti-idiotype and free idiotype were established. While showing specificity for their respective inducing monoclonals, anti-idiotypes also cross reacted in varying degrees with other anti-pGH monoclonals regardless of specificity differences between the antibodies, demonstrating the presence of a cross-reactive idiotype.

Structural characterization of viral neutralizing monoclonal antibodies to hepatitis B surface antigen

In this study we describe the viral neutralizing activity of murine monoclonal antibodies (MAb) specific for hepatitis B surface antigen (HBsAg). This viral neutralizing activity was assessed in vitro by employing Hepatitis Delta Virus (HDV) and human hepatocytes as target cells. To further characterize these viral neutralizing antibodies we generated a panel of anti-idiotypic (anti-Id) reagents and serologically characterized these antibodies for epitope specificity, Id specificity, and Id heterogeneity. Direct binding and competitive inhibition solid phase enzyme immunoassay have demonstrated that two murine MAb specific for HBsAg (anti-HBs), designated A1.2 and A3.1, recognize similar or overlapping epitopes on HBsAg, while monoclonal anti-HBs, designated A2.1 recognizes a unique HBsAg epitope. Further, Id analysis using monoclonal and polyclonal anti-Id reagents have identified both a private and a cross-reactive Id, respectively, on the anti-HBs, A1.2 preparation. The source of the idiotypic cross-reactivity between A1.2 and A3.1 has been identified, using Western blot analysis, to conformational determinants expressed by the heavy (H) and light (L) chains of these monoclonal anti-HBs. Lastly, the intrastrain antibody repertoire induced following HBsAg immunization was found to be relatively restricted in heterogeneity by clonotype analysis using isoelectric focusing and affinity immunoblot analysis. Interspecies variability in the anti-HBs response was observed based on epitope recognition using purified anti-HBs from a variety of species.

Immunogenic Properties of an Anti-DNA Antibody- Derived Peptide, 88H.64-80: Location of a Dominant Idiotope Defined by T and B Cells

Immunization of normal (BALB/c×NZW)F1H-2d×umice with peptide 88H.64-80 derived from the framework (FR) 3 VH region sequence of anti-DNA mAb, V-88, induces the production of IgG anti-peptide antibodies which cross-react specifically with the parent mAb. However, immunization of these normal mice with peptide 88H.64-80 sometimes provokes increased production of anti-dsDNA antibodies. A set of alanine substitute homologues of peptide 88H.64-80 were made to identify the amino acid residues that contribute to the antigenic status of the peptide. Peptide 88H.64-80 contained an antibody epitope at the carboxyl terminus of the peptide, while substitution of particular residues throughout the peptide had a significant inhibitory effect on T cell stimulation. Finally, subclass analysis of IgG anti-88H.64-80 peptide antibodies revealed a close correlation between the production of IgG2aanti-peptide antibodies (associated with a TH1 T cell response) and the production of IgG anti-dsDNA antibodies, but there was no correlation with any other antibody subclass. Despite the ability of peptide 88H.64-80 to provoke both the production of anti-dsDNA antibodies as well as anti-V region antibodies, the sequence of this peptide differs by only one amino acid residue from a number of murine germline gene-encoded homologues. Peptide 88H.64-80 probably represents an epitope whose appearance correlates with the level of expression of the VH genes that carry its sequence, and as such is characteristic of cross-reactive idiotypes associated with pathology.

The frequent expansion of a subpopulation of B cells that express RF-associated cross-reactive idiotypes: evidence from analysis of a panel autoreactive monoclonal antibodies.

Preferential expression of VH gene segments is evident within the adult human primary B-cell repertoire. The repertoire may be influenced by genetic factors, e.g. VH gene segment polymorphisms, or in a temporal manner due to the exposure to environmental antigens. The molecular characteristics of 15 autoreactive human monoclonal antibodies (MoAbs) are reported. All antibodies were of the IgM isotype, and 12 of the 15 were polyreactive and included rheumatoid factor type specificity, i.e. reactivity with IgG. Nine of the 15 MoAbs are products of VH3 gene segments, as evidenced by staphylococcal protein A binding; four of these express the cross-reactive idiotype recognized by the mouse MoAb 3H7 and are thus products of the VH26 gene segment. One of the five remaining VH3 gene products expresses the cross-reactive idiotypes recognized by the mouse MoAbs B6 and D12. V-gene family usage, determined by polymerase chain reaction (PCR) amplification of cDNA and further hybridization with family-specific oligonucleotide probes, confirmed the cross-reactive idiotype studies and showed that only VH3-gene-encoded proteins bound staphylococcal protein A. Five of the six non-VH3 gene segment products express the cross-reactive idiotype recognized by the mouse MoAb LC1 and could be assumed to be products of the VH4.21 gene segment; however, one human MoAb is shown to be the product of a VH2 gene segment. This is interesting because it turns LC1 from being an anti-cross-reactive idiotype antibody into an anticlan reagent.

Natural antibodies that react with V-region peptide epitopes of DNA-binding antibodies are made by mice with systemic lupus erythematosus as disease develops.

Cross-reactive idiotypes (CRI) have been detected on anti-DNA autoantibodies associated with lesions typical of systemic lupus erythematosus. In order to analyse the antigenic make up of idiotypes on anti-DNA monoclonal antibodies (mAb) V-88 (IgG1 kappa) and F-423 (IgG3 kappa), derived respectively from an adult (NZB x NZW)F1 and a fetal MRL/Mp-lpr/lpr mouse, a set of overlapping hexapeptides representing the VH and VL regions of mAb V-88 and F-423 were synthesized and reacted with a range of sera in pepscan enzyme-linked immunosorbent assays (ELISA) taken from normal and lupus mouse strains. Serum pools were collected both from normal BALB/c and lupus MRL/Mp-lpr/lpr and (NZB x NZW)F1 mice at 10, 20 and 30 weeks of age and analysed for the presence of spontaneously produced anti-V-region peptide IgM and IgG antibodies. IgM antibodies from both the lupus mice reacted with the same V-region epitopes, and although some epitopes mapped to similar locations in the two mAb, the maps for V-88 and F-423 were not identical. In MRL/Mp-lpr/lpr mice, as lupus disease progressed there was a switch from IgM antibodies to IgG anti-peptide antibodies whose specificity for the peptide antigens coincided with but was better defined than that of the IgM antibodies. The identified idiotopes were located in both complementary determining regions (CDR) and framework region (FR) regions, indicating that some contribute to CRI shared by other related antibodies, while others were unique to either mAb V-88 or F-423. In conclusion, we have dissected and identified a mosaic of antibody V-region idiotopes that contribute to the idiotype of an anti-DNA autoantibody and against which autoantibodies are made naturally in lupus disease.

Idiotypic Analysis of Anti-Nucleosome Monoclonal Antibodies Derived from Lupus Mice

3F6 and 2E1 are anti-(H2A-H2B) monoclonal antibodies derived from a 12-month-old (NZB×NZW)F1 mouse that diverged from the same clonal precursor by somatic mutations. Rabbit anti-idiotypic antisera were prepared against these two monoclonal antibodies and used as probes to analyse the properties and expression of 3F6 and 2E1 idiotypes. Both idiotypes were conformational, distant from the antigen binding site and did not correlate with a VH- or VL-chain usage. 3F6 was preferentially bound by anti-3F6 idiotype but was weakly recognized by anti-2E1 idiotype suggesting, since 3F6 derives from 2E1, that 3F6 bore idiotypic determinants generated by somatic mutations. While none of the murine anti-DNA monoclonal antibodies tested expressed 2E1 or 3F6 idiotypes, 3F6 idiotype could be detected on approximately one-third of anti-(H2A-H2B) monoclonal antibodies derived from other lupus strains of mice, demonstrating the presence of cross-reactive idiotypes on autoantibodies directed against a nucleosome that could result from somatic mutations.

Incidence of anti-mouse antibodies in thrombocytopenic patients with autoimmune disorders

Idiopathic thrombotycopenic purpura (ITP) is an autoimmune disorder in which circulating autoantibodies react with target antigens on the platelet membrane. In order to identify the autoimmune response in ITP, two MAIPA (Monoclonal Antibody (MAb) Immobilization of Platelet Antigen) assays (MAIPA I and MAIPA II) were performed on sera from thrombocytopenic patients. In the classic MAIPA assay (MAIPA I), control platelets were incubated simultaneously with human serum and a mouse MAb to a platelet glycoprotein. In MAIPA II, the control platelets were incubated first with the human serum and then, after washing, with the selected mouse MAb. A positive MAIPA I test but a negative MAIPA II has been shown to result from the presence of serum antibodies recognizing mouse MAb to platelet glycoproteins used in the assay. We compared the frequency of such 'anti-mouse' antibodies in patients with thrombocytopenia associated or not with other autoimmune states and in healthy donors with a normal platelet count. Statistically significant differences were found in the incidence of anti-mouse antibodies between patients and healthy donors. Furthermore, the identity of the targeted mouse MAbs varied in sera from the patients. The detected anti-mouse antibodies may include anti-idiotypic antibodies produced against cross-reactive idiotypes shared by human and mouse anti-platelet antibodies.

Functional expression of the IGKV A18b gene and its idiotypic cross-reactivity with the A2 variable region.

Functional expression of the IGKV A18b gene and its idiotypic cross-reactivity with the A2 variable region.

BCell Superantigens in HIV-1 Infection

HIV-1 infection affects many of the cellular components vital for the maintenance of immune homeostasis. Similar to the T cell superantigen effect on T cell expansion and depletion in AIDS, HIV components with B cell superantigenic properties could be responsible for the observed B cell activation and skewing of VH family usage. Current data on possible B cell superantigen properties of HIV proteins (gp120) are mostly based on studies describing the clonality and VH family usage of immunoglobulins in HIV infection. Various laboratories reported independently an unusual skewing of the VH-repertoire of antibodies that appears not to be random. According to these observations, an enrichment of VH 1 and VH4 family - paralleled a depletion of VH3 family - utilizing anti-HIV-1 gp120 and p24 antibodies in HIV-1 infected individuals and a loss of total VH3+ Ig in patients with late stages of AIDS. Polyclonal and monoclonal (VH1, VH4, and VH5) anti-p24 and gp120 antibodies share a crossreactive idiotype (IF7). IF7 like antibodies were found in the serum of HIV-1 infected individuals, persisting in the course of infection, perhaps contributing to the depletion of VH3+ Ig. Furthermore, a restriction of clonal heterogeneity of anti-p24 and anti-gp120 antibodies was detected by isoelectric focusing and indicated by skewed kappa/lambda light chain isotype ratios, indicating clonal dominance of certain sets of anti-HIV-1 antibodies during infection. Taken these findings together, a strong case for the involvement of a B cell superantigen can be made, although the mechanism of B cell depletion is not fully understood.

Function and expression of a human idiotypic network in Schistosomiasis japonica.

The cross-reactive idiotype (Hu-SJ-CRIM) is defined by polyclonal human anti-idiotypic antibodies derived from chronically S. japonicum infected patients. The present study shows that serum levels of Hu-SJ-CRIM expressed by antibodies to S. japonicum soluble egg antigen (SEA) are associated with acute infection and hepatosplenic disease. Xenogeneic anti-idiotypic antisera (anti-Hu-SJ-CRIM) suppressed human lymphocyte blastogenesis to SEA in vitro by 47-82% (P < 0.05). These anti-idiotypic antibodies also suppressed in vitro granuloma formation induced by SEA coated heads in a dose dependent manner. This immunosuppression was antigen specific in that mitogen (PHA) or non-related antigen (PPD) induced blastogenic responses were not suppressed. Surprisingly, anti-idiotypic antibodies (anti-SJ-CRIM), which describe the mouse correlate CRIM were not suppressive in the human blastogenesis or in vitro granuloma formation assays. These data indicate a dichotomy in the function and specificity of the idiotype/anti-idiotype human and murine immune networks in S. japonicum infection. Thus, only the patient derived molecules and serology form the basis for an immunoregulatory network in Schistosomiasis japonica.

Mixed monoclonal cryoglobulinemia and monoclonal rheumatoid factor cross-reactive idiotypes as predictive factors for the development of lymphoma in primary Sjögren's syndrome.

To prospectively investigate whether mixed monoclonal cryoglobulinemia (MMC) and monoclonal rheumatoid factor (mRF)-associated cross-reactive idiotypes (CRI) serve as predictive factors for the development of lymphoma in patients with primary Sjögren's syndrome (SS). One hundred three consecutive patients with primary SS were evaluated from 1986 to 1991. In all patients, the amount of cryoglobulin was measured by ultraviolet absorption at 280 nm and 260 nm. The type of cryoglobulinemia was identified by agarose gel electrophoresis, combined with immunofixation. Sera from all patients were evaluated by enzyme-linked immunosorbent assay, using the corresponding monoclonal or polyclonal antibodies, for the presence of immunoglobulins bearing the idiotypes 17109 (V kappa IIIb associated), G-6 (VH1 associated), and 3rd SS (a rabbit polyclonal antibody raised against the Fab fragment of an IgM kappa mRF from a patient with primary SS). Data analysis was performed by logistic regression. Eighteen of the patients with primary SS (17.4%) had MMC during the first evaluation. There was a statistically significant correlation between the presence of MMC and a higher prevalence of autoantibodies to Ro/SS-A and La/SS-B, as well as extraglandular manifestations. During a 5-year period, 7 patients developed lymphoma. Six of the 7 (86%) had MMC before the appearance of lymphoma, compared with 12 of 96 (12.4%) of the remainder (r = 0.421, P < 0.0009). Patients who developed lymphoma had higher amounts of cryoglobulin than those who did not (mean +/- SD 53.4 +/- 44.7 mg/dl versus 26.8 +/- 20.6 mg/dl). CRIs 17109 and G-6 were also correlated with lymphoma development (r = 0.321, P < 0.006 and r = 0.22, P < 0.03, respectively). For both CRIs, this correlation was dependent on the presence of MMC, since a stepwise multiple comparison analysis revealed that their individual significance was abolished when their correlation with lymphoma in association with MMC was assessed. The determination of MMC can be used as a laboratory predictive factor for lymphoma development in primary SS. CRIs 17109 and G-6 may also be used to predict lymphoma development, especially when the monoclonal component is absent.

Clinicopathological factors relating malignant lymphomawith sjögren's syndrome

This study was undertaken to summarize the current status of the clinicopathologicfactors related to non-Hodgkin's lymphoma (NHL) development in patients with Sjögren's syndrome (SS). Through a MEDLINE search, pertinent articles on SS, monoclonality, and NHL were found and reviewed. Malignant lymphoma description was based on the International Lymphoma Study Group classification. Patients with SS are known to have an increased risk for developing B-cell NHL (B-NHL). However, such a complication occurs in less than 10% of patients, being reported mainly in those with primary SS. Extranodal low-grade B-NHL are observed most frequently. Persistent enlargement of parotid glands, adenopathy, monoclonal gammopathy, and crossreactive idiotypes are all signs suggesting possible lymphoma evolution. Although monoclonality does not mean malignancy unequivocally, it is considered to be a precursor for NHL development in SS. Factors implicated into lymphomagenesis in SS include dysregulation in the mechanisms leading to apoptosis, hyperstimulation of B-1 cells, and an infectious agent. Polyclonal lymphoproliferation characterizing SS might in some instances transform into monoclonal, and then to malignancy. Further studies on the mechanism whereby NHL develops in SS are warranted.

Rheumatoid factor idiotypes in patients with Sjögren's syndrome

Sjögren's syndrome (SS) is a systemic as well as an organ-specific autoimmune disease, characterized by multiple organ damages, autoantibody production such as rheumatoid factor (RF), and also by the development of lymphoproliferative disorders such as monoclonal gammopathy or malignant lymphoma. We produced two monoclonal anti-idotypic (ld) antibodies (A-SF 18/2 and A-AMB 1/5) against monoclonal RFs (IgA-L and IgM-K) derived from patients with SS. Expression of the cross-reactive idiotype (CRI) of these monoclonal RFs was studied in 101 patients with SS, 71 with rheumatoid arthritis (RA) without complication of SS and 93 normal subjects. The results showed the followings: (1) By the enzyme-linked immunosorbent assay (ELISA), 17.8% and 15.8% of patients with SS and 15.5% and 21.7% of patients with RA showed CRI of SF 18/2 and AMB 1/5, respectively, whereas 6.5% and 5.7% of normal subjects showed these CRIs, respectively, (2) In the SF 18/2 Id system, there was one group (45%) in SS patients who showed weak positive CRI, whereas there was no such group in the AMB 1/5 Id system, (3) Out of 15 patients with SS, there were 4 patients whose peripheral blood lymphocytes had a significant amount of surface membrane Id of SF 18/2 (9.1-37.7%), suggesting the existence of a monoclonal population in the blood. These data suggest that clones with one particular SF 18/2 Id were markedly activated in SS patients and these may be related to the monoclonal proliferation of RF Id-positive B cells in patients with SS.

A Patient with Autoimmune Thrombocytopenic Purpura Demonstrating Serum Antibodies Reactive with Mouse Cross-Reactive Idiotypes

Autoimmune thrombocytopenic purpura (ATP) is a syndrome of destructive thrombocytopenia due to platelet-binding antibodies. We report the case of a young woman (C.V.) who has a history of chronic ATP with severe but transient bouts of thrombocytopenia. Using the classic monoclonal antibody (MAb) immobilization of platelet antigens (MAIPA) assay to screen serum antibody specificity, results were strongly positive with MAbs to glycoproteins (GPs) Ib-IX, Ia-IIa, IV, and p24, but weakly positive or negative for GP IIb-IIIa. In contrast, a two-step incubation assay (MAIPA II), in which platelets were incubated sequentially with C.V. serum and the murine MAb, gave negative results for all GPs. Affinity chromatography performed using Bx-1, a MAb to GP Ib, showed that the patient's serum contained antibodies to determinants expressed by mouse immunoglobulins. These were present on Fab fragments of Bx-1. A survey of sera from other patients with thrombocytopenia of immune origin revealed that antibodies reactive with selected idiotypes of mouse MAbs were not infrequent and raises the question of their role in the thrombocytopenia.

Identification of an idiotypic peptide recognized by autoantibodies in human immunodeficiency virus-1-infected individuals.

Antibodies against HIV-1 proteins in HIV-1-infected individuals share a cross-reactive idiotype defined by the monoclonal antiidiotypic antibody 1F7 (5). Using a computer algorithm based on the molecular recognition theory, regions of inverse hydropathy between the variable sequence of 1F7 and human monoclonal anti-HIV-1 antibodies were identified, which are assumed to be involved in idiotype-antiidiotype contacts. A peptide was designed from the proposed contact in the variable heavy chain framework 3-complementarity determining region 3 (FR3-CDR3) of human antibodies and was synthesized. This peptide is recognized by the antiidiotype 1F7 and inhibits the binding of 1F7 to human anti-HIV-1 antibodies which express the 1F7 idiotype. A survey of normal and HIV-1-infected sera revealed the presence of antibodies in infected sera which bind to the FR3-CDR3 peptide. The biological relevance of autoantibodies against a self idiotope associated with HIV-1 infection is discussed in the context of the regulation of the antibody response to HIV-1.

Assessment of a functional role of auto-anti-idiotypes in idiotype dominance.

We have used a well-defined idiotypic system, the cross-reactive idiotype of A strain (CRIA) (Ab1) idiotype generated in A/J mice injected with arsonate coupled to keyhole limpet hemocyanin (ARS-KLH), to determine the frequency of precursors for auto-anti-idiotypic antibodies (auto-Ab2) in naive and immunized A/J mice by limiting dilution analysis after polyclonal activation by lipopolysaccharide. In naive animals, the precursor frequencies of auto-Ab2 B cells were below the limit of sensitivity of the technique in the majority of A/J mice, and could be detected in only 20% of the animals. Upon immunization with ARS-KLH, a large increase in auto-Ab2 precursor frequency was observed. This shift in frequency was not found when A/J mice were injected with KLH alone, or when BALB/c mice, which do not express the CRIA idiotype, were injected with ARS-KLH. To study the functional role of the auto-Ab2 B cells, we injected neonatal A/J mice with polyclonal rabbit Ab3 antibodies directed against a recurrent idiotype of auto-Ab2. Thereafter, these mice were injected with ARS-KLH. Although the anti-arsonate response level was normal, the CRIA Ab1 expression was reduced tenfold. Thus, the suppression of auto-Ab2 affects Ab1 dominance. We further show that the presence of maternal Ab1 can strongly modify the immune response of the offspring by inducing higher levels of the idiotype after immunization. Furthermore, IgM anti-arsonate antibodies were detected before immunization with antigen. From these data, we conclude that the affinity of antigen alone cannot explain the dominance of CRIA. Network selection is important in the shaping of the available repertoire.

The perinatal presence of antigen (p-azophenylarsonate) or anti-mu antibodies lead to the loss of the recurrent idiotype (CRIA) in A/J mice.

The immune response of A/J mice against p-azophenylarsonate (Ars)-keyhole limpet hemocyanin (KLH) is characterized by the dominance, late in primary and during the secondary, of a recurrent idiotype called CRIA, encoded by a canonical combination of Ig gene segments. In this study, A/J mice were given Ars coupled to deaggregated human gamma globulins (dHGG) within 24 h after delivery. The offsprings from these mice were then exposed as adults to Ars-KLH. These animals developed an unusual immune response. The level of anti-Ars antibodies was nearly normal but a dramatic shift in repertoire was observed: the cross-reactive idiotype which is the hallmark of the anti-Ars response in A/J mice was completely absent. The idiotype could be recovered by injection of anti-idiotypic antibodies alone, with no need of lipopolysaccharide coupling. Therefore the presence of antigen at birth can lead to a strong perturbation of idiotype selection. Similar results were obtained with neonatal treatment using anti-IgM antibodies. After recovery of suppression, A/J mice can mount an anti-arsonate response of normal level but devoid of the dominant idiotype.

Transient dominance of the early primary immune response by a highly conserved B-cell clone that is distinguished by its lack of memory, high threshold of activation, and a high affinity

We establish here that the very early primary response to the hapten phthalate (Xmp) is distinguished by a restricted heterogeneity with over 80% of the anti-Xmp antibodies expressing a single well-defined cross-reactive idiotype (CRI Xmp-1) associated with a previously described highly conserved clonotype that is expressed by most inbred strains of mice and many outbred mouse populations as well. The characteristic early dominance of this one clonotype in the primary response is transient. While the CRI Xmp-1 clonotype is present later in the primary and throughout the secondary response, it represents only a very small proportion of the total anti-Xmp antibody population at these times. The early dominance of the single clonotype is rapidly replaced by a heterogeneous population of antibodies. Differential activation thresholds for the primary response clonotype (CRI Xmp-1) and secondary response clonotypes, and the failure of the dominant primary response clonotype to expand in the secondary response (i.e., absence of memory) suggest the presence of two distinct B-cell lineages.