Rabbit Anti-idiotypic Antibodies Research Articles

Targeting Pemphigus Autoantibodies through their Heavy-Chain Variable Region Genes

Pemphigus vulgaris (PV) is a potentially fatal blistering disease characterized by autoantibodies against cell surface adhesion proteins desmoglein (Dsg) 3 and Dsg1. Previous studies using phage display to clone Dsg-reactive monoclonal antibodies from a PV patient demonstrated that a limited number of antibody variable region genes encode the autoantibody repertoire, with different genes for pathogenic and non-pathogenic mAbs. Here, we investigated the feasibility of specific autoantibody targeting in pemphigus. We produced rabbit anti-idiotypic antibodies against two pathogenic and two non-pathogenic PV mAbs. Antisera inhibited binding of the immunizing mAb to Dsgs by ELISA as well as pathogenicity against cultured human keratinocytes. Antisera also inhibited other mAbs using the same variable region heavy chain (V(H)) genes, despite different light chains or somatic mutations. Additionally, peptide phage display identified peptide sequences that bound PV mAbs in a V(H)-specific manner. To evaluate the therapeutic potential of V(H) gene-targeted reagents, preimmune sera and antisera were used to adsorb pathogenic antibodies from PV sera. Pooled antisera significantly reduced pathogenic activity from the original PV patient's serum and bound pathogenic antibodies from two other PV sera, suggesting shared autoantibody V(H) gene usage among PV patients. Together, these data suggest novel V(H) gene-targeted approaches toward PV treatment.

Inhibitory ADAMTS13 Monoclonal Autoantibodies Cloned from TTP Patients Show Restricted Gene Usage, Inhibit Murine ADAMTS13, and Are Blocked by Rabbit Anti-Idiotypic Antibodies.

Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal disorder often associated with autoantibody inhibition of ADAMTS13, a VWF-cleaving protease. Autoantibodies decrease ADAMTS13 activity resulting in accumulation of “unusually” large VWF multimers that mediate platelet thrombosis. To better understand the role autoantibodies play in disease pathogenesis, as well as to develop more specific methods for diagnosis and therapy, it is necessary to characterize pathogenic antibodies on a molecular level, something not possible through analysis of polyclonal patient antisera. The ability to clone large repertoires of patient monoclonal autoantibodies (mAbs) using phage display offers a unique opportunity to address this issue. Three patient (Pt) antibody phage display libraries were created from either splenocytes (Pt1) or peripheral blood lymphocytes (Pt2, Pt3) of individuals with acquired TTP. ADAMTS13-specific mAbs were isolated by panning against recombinant ADAMTS13. Unique clones were identified by DNA sequencing, and their ability to interact with ADAMTS13 was characterized. After antigen selection of Pt1 library, 56 mAbs were randomly-selected from panning rounds 2 through 4 and 68% were found to comprise heavy chains encoded by VH1-69 paired with a VL3 family lambda light chain (3h or 3m). The remaining mAbs comprised heavy chains from the VH1, 3, or 4 families usually paired with kappa light chains. For Pt2 and Pt3 libraries, there was an identical pattern of genetic restriction in immune response to ADAMTS13, i.e. 16 of 24 mAbs (Pt2) and 27 of 27 mAbs (Pt3) were encoded by VH1-69 heavy chains and VL3 family lambda light chains. Though nearly all mAbs were unique, common CDR3 regions among some of the mAbs provided evidence of B-cell clonal expansion and somatic mutation. Though all mAbs bound to ADAMTS13 irrespective of genetic origin, mAbs comprising a VH1-69 heavy chain paired with a VL3 light chain inhibited ADAMTS13 using the FRET-VW73 assay while mAbs comprising a VH1-69 paired with a kappa light chain or comprising non-VH1-69 heavy chains did not inhibit ADAMTS13, with only two exceptions. MAb binding to ADAMTS13 was blocked by preincubation with normal human or murine plasma, but much less so by plasma from TTP patients or ADAMTS13 knockout mice suggesting crossreactivity with mouse ADAMTS13. Certain human mAbs inhibited cleavage of FRET-VWF73 by mouse ADAMTS13 and also inhibited ADAMTS13 in vivo after injection into the internal jugular vein of mice. Rabbit anti-idiotypic antibodies raised against mAb 416, a prototypical VH1-69-encoded mAb, blocked 416's ability to inhibit human ADAMTS13. Taken together, the cloning and analyses of a large cohort of ADAMTS13 inhibitory autoantibodies derived from 3 unrelated individuals with acquired TTP revealed a genetically restricted immune response. This feature, if common among TTP patients, offers a potential therapeutic target for treatment of TTP, e.g. selective deletion of B-cells utilizing the VH1-69 heavy chain gene. Furthermore, crossreactivity of some human mAbs with murine ADAMTS13 provides a mouse model of acquired ADAMTS13 deficiency that may prove useful for determining the role of autoantibodies in the pathogenesis of TTP, particularly in the context of additional factors (e.g. environmental) that may be required to trigger the disease. Finally, anti-idiotypic mAbs, currently being cloned from rabbit phage display libraries, may help identify pathogenic antibodies in patient plasma and/or lead to novel therapeutic approaches.

Reduced expression of serotonin receptor(s) in the left colon of patients with colonic inertia.

Serotonin regulates colonic motility receptors expressed on neural fibers and smooth muscle. Colonic inertia is characterized by delayed colonic transit. Abnormalities in serotonin receptor protein, as judged by immunoreactivity levels, could contribute to the origin of colonic inertia. The aim of this study was to investigate the expression of serotonin receptor(s) immunoreactivity in the left colon of patients with colonic inertia compared with controls. Sixteen patients who underwent subtotal colectomy for colonic inertia were assessed. Colonic transit time was measured with the radiopaque marker technique and presented as the number of retained markers in the colon on Day 5. The control group consisted of 18 patients who underwent left hemicolectomy for colonic carcinoma; histologically normal tissues from the left colon were used. Immunohistochemical staining for serotonin receptor was performed with a rabbit anti-idiotypic antibody. The average positive area (square pixels) in the mucosa, muscularis mucosa, submucosa, and circular and longitudinal muscles per microscopic field (63x) was calculated based on measurement of the positively stained area in 20 randomly chosen microscopic fields in each related structure. The Scion Image computer analysis system was used. Serotonin receptor(s) immunoreactivity was mainly detected in the muscular mucosa, circular muscles, and longitudinal muscles and rarely in the mucosa and submucosa. In muscularis mucosa and circular muscle, the positive areas were significantly less in the colonic inertia group than in controls (muscularis mucosa: 29.1 +/- 10.8 vs 109.7 +/- 28.2, P < 0.05; circular muscle: 25.6 +/- 6.2 vs 90.2 +/- 19.1, P < 0.01). There were significantly positive correlations in the control group in serotonin receptor(s) immunoreactivity levels between circular muscle and longitudinal muscle (r = 0.54, P < 0.05) and between muscular mucosa and longitudinal muscle (r = 0.57, P < 0.05) but not in colonic inertia patients. In addition, the positive areas in the circular muscle were positively correlated to the colonic transit time (Spearman's rank correlation, 0.83; P < 0.01). In colonic inertia patients, the serotonin receptor(s) immunoreactivity level is lower in muscular mucosa and circular muscle. The absence of a correlation of serotonin receptor(s) immunoreactivity in the muscular mucosa and muscularis propria in the patient group implies that an uncoordinated expression of serotonin receptors may also contribute to colonic inertia. However, the positive correlation between serotonin receptor(s) immunoreactivity levels in the circular muscle and the transit time observed in colonic inertia patients suggests a decrease in stimulatory subtypes and at the same time an increase in inhibitory subtypes of serotonin receptors in this tissue.

Monoclonal antibodies to amoxicillin express different idiotypes determined by anti-idiotype antibodies production.

Penicillins are beta-lactam antibiotics able to generate several antigenic determinants that are recognized by the immune system. To study the differences in the antigen binding site of two monoclonal antibodies (Mab) specific to amoxicillin, polyclonal rabbit anti-idiotypic antibodies were produced. One Mab, AO3.2 (IgG2a), specific to a structure formed by the acyl-side chain structure and a part of the nuclear region of amoxicillin. The second one, AO6.2 (IgE), is specific to the side chain of amoxicillin, although it also recognizes the side chain of other penicillins (penicillin G and ampicillin). These antibodies were used to immunize rabbits in order to produce polyclonal anti-idiotypic antibodies, which were purified in several steps by affinity chromatography. The specificity and cross-reactivity studies were made by ELISA and ELISA inhibition. The results suggest that the anti-Id antibodies produced are the internal image of the antigen, since the binding to their specific idiotype is blocked mainly by the original hapten (amoxicillin): in 98% of the cases with anti-id-1 (induced against AO3.2) and in 59% with anti-id-2 (induced against AO6.2). The absence of cross-reactivity of each anti-idiotypic antibody with the different Mabs specific to amoxicillin shows that the idiotypes induced by the same hapten have differences that are reflected by the nonrecognition of these anti-idiotypes. We conclude that such a small molecule as amoxicillin can present several antigenic determinants that induce a panel of antibody specificities especially directed against the side chain.

Anti-anti-idiotypic (Ab3) antibodies that bind progesterone-11alpha-bovine serum albumin differ in their combining sites from antibodies raised directly against the antigen.

Polyclonal rabbit anti-idiotypic (Ab2) antibodies raised against the antiprogesterone mAb DB3 (Ab1) were used to induce an Ab3 antiprogesterone response in BALB/c mice. While the affinity of Ab3 sera for progesterone was 10-50-times lower than that of DB3, their steroid-binding specificity showed considerable similarity to DB3. Two immunoglobulin M (IgM) Ab3 monoclonal antibodies (mAbs), 1A4 and 3B11, were obtained, both of which bound progesterone conjugated to bovine serum albumin (progesterone-BSA). 1A4 also bound free progesterone, although with low affinity and very broad cross-reactivity. Like DB3, 1A4 is encoded by a heavy-chain variable region (VH) gene segment from the small VGAM3.8 family, a restriction that is characteristic of antibodies raised against progesterone-11alpha-BSA. In contrast, 3B11 binds progesterone-11alpha-BSA but not free progesterone and is encoded by an unrelated VH gene from the J558 family. The light chain variable region (VL) of 1A4 lacks the intradomain disulphide bridge owing to replacement of CysL23 by Tyr. Both the 1A4 and 3B11 heavy chains have extremely short complementarity determining region (CDR) H3 loops, comprising three and four amino acids, respectively. Modelling of the combining site of 1A4 from the X-ray crystallographic structure of DB3 indicates that the short H3 loop is a major factor in the loss of affinity and specificity for steroid.

Dissection of an antibody paratope into peptides discloses the idiotope recognized by the cognate anti-idiotypic antibody

Using methods of parallel synthesis, the complete amino acid sequence of an Ab 1 antibody (Tg 10, an anti-human thyroglobulin monoclonal antibody) was made in the form of a set of 100 synthetic overlapping peptides. This set of immobilized peptides was allowed to react with the cognate Ab2 (AI 10, a highly purified rabbit anti-idiotypic polyclonal antibody to Tg 10). A dominant peptide idiotope, INTFSGVPTYA, was thus mapped, which corresponds mainly to the CDR2 region from the V H domain of the Tg 10 mAb. A synthetic peptide replica of this idiotope was found to bind to AI 10 with an affinity ( K D in the 10 −8 M range, as measured using BIACORE technology) which represents a significant part of the affinity of the complete Tg 10 antibody ( K D in the 10 −9 M range). The synthetic peptide also elicited anti-idiotypic antibodies in rabbits that recognized specifically the Ab1 antibody in an Ab1- and antigen-inhibitable manner. The peptide idiotope was further characterized chemically by the identification of residues important for binding to the Ab2 and by modelization of its structure. Our approach makes it readily possible to map and characterize functional, continuous-type idiotopes that could be further used to manipulate the immune response by peptide technologies.

Anti-idiotype technique: an alternative approach for immunodiagnosis of bluetongue

In development of a bluetongue alternative immunodiagnostic rest, the polyclonal anti-idiotypic antibodies were generated by the sequential immunization of rabbits with three monoclonal antibodies to VP7 of bluetongue virus. The anti-idiotypic antibodies recognize the idiotypes that are located within or near the antigen-combining sites and are associated with both heavy and light chains of the antibodies to VP7 of bluetongue virus. The anti-idiotypic antibodies mimic the VP7 antigen by recognizing the anti-VP7 antibodies from cattle and sheep that were infected with various serotypes of bluetongue viruses. The results indicate that the rabbit anti-idiotypic antibodies may be used as surrogate antigen in serological assays to detect the antibodies from different species of animals infected with various serotypes of bluetongue viruses.

Adjuvant effect of anti-idiotypic antibodies to Yersinia pestis lipopolysaccharide.

Rabbit anti-idiotypic antibodies (anti-Id-ab) against Yersinia pestis lipopolysaccharide (LPS) were obtained with monoclonal immunoglobulins. Their complementary character to the original antigen was confirmed by immunohistochemical analysis and ELISA and gel precipitation tests. The anti-Id-ab were shown to possess all essential properties of Ab2beta subtype. Both in-vitro and in-vivo experiments demonstrated a pronounced adjuvant activity of anti-Id-ab without the toxic effect characteristic of Y. pestis LPS. Combined immunisation with anti-Id-ab plus the FI capsular antigen led to a significant increase in the protective immune response against experimental acute challenge with virulent Y. pestis.

A recombinant single chain antibody neutralizes coronavirus infectivity but only slightly delays lethal infection of mice.

The variable region genes of a murine anti‐coronavirus monoclonal antibody (mAb) were joined by assembly polymerase chain reaction and expressed in Escherichia coli in a single chain variable fragment (scFv) configuration. After induction of expression, the expected 32‐kDa protein was identified by Western immunoblotting with specific rabbit anti‐idiotype antibodies. The scFv fragments were purified from soluble cytoplasmic preparations by affinity chromatography on nickel agarose, which was possible with an N‐terminal but not with a C‐terminal histidine tag. Purified scFv fragments retained the antigen‐binding properties of the parental antibody, could inhibit its binding to viral antigens with apparently higher efficiency than monovalent antigen‐binding (Fab) fragments, but neutralized viral infectivity with lower efficiency (about sevenfold at a molar level). To evaluate the usefulness of these smaller and less immunogenic molecules in the treatment of viral diseases, mice were treated with purified recombinant scFv fragments and challenged with a lethal viral dose. A small delay in mortality was observed for the scFv‐treated animals. Therefore, even though the scFv could neutralize viral infectivity in vitro, the same quantity of fragments that partially protected mice in the form of Fab only slightly delayed virus‐induced lethality when injected as scFv fragments, probably because of a much faster in vivo clearance: the biologic half‐life was estimated to be about 6 min. Since a scFv derived from a highly neutralizing and protective mAb is only marginally effective in the passive protection of mice from lethal viral infection, the use of such reagents for viral immunotherapy will require strategies to overcome stability limitations.

Evidence that two distinct populations of rabbit anti-idiotypic antibodies are induced by three monoclonal antibodies specific for bluetongue virus core protein VP7.

Three groups of anti-idiotypic antibodies (anti-Id or Ab2), designated RAb2-A, RAb2-B1, and RAb2-B2, were isolated from rabbit antiserum raised against three monoclonal antibodies (mAbs) (M1875, M1877, and M1886) specific for the bluetongue virus core protein, VP7. RAb2-A was specific for the idiotype of M1875. RAb2-B1 and RAb2-B2, isolated through the M1877 and M1886 affinity columns, respectively, were directed against the common idiotype that is shared by M1877 and M1886 and therefore classified in the same population (RAb2-B). Further characterization revealed that the two anti-Id populations, RAb2-A and RAb2-B, were significantly different. RAb2-A was an Ab2 beta type of anti-Id since (i) its reaction with M1875 was inhibited by the antigen; (ii) it inhibited the M1875-VP7 interaction; and (iii) it elicited anti-VP7 antibody response in Balb/c mice. In contrast, RAb2-B may represent an Ab2 alpha type of anti-Id since its reactions with M1877 or M1886 were not inhibited by the antigen, even though it inhibited mAbs from binding to the antigen. These results indicated that RAb2-A and RAb2-B represent two distinct populations of anti-Ids to anti-VP7 mAbs with similar epitope specificity.

Induction of antibodies to the bluetongue virus core polypeptide VP7 in sheep by internal image rabbit antiidiotypic antibodies.

We previously generated rabbit polyclonal antiidiotypic antibody (anti-Id) to a murine monoclonal antibody (M1875) specific for the bluetongue virus core protein VP7, and demonstrated that this anti-Id (designated RAb2-A) had the characteristics of an internal image anti-Id (Ab2 beta). In this communication, RAb2-A was used to induce immune responses in sheep and the responses were compared to immunization with VP7. The immune sera were tested for the presence of anti-VP7 antibodies and the expression of the Id of M1875. Animals immunized with RAb2-A were able to produce M1875-like antibody responses, i.e., they recognized the same or a similar epitope as M1875 and possessed the M1875 Id, without subsequent exposure to the original antigen. This was demonstrated by showing that antibodies induced by RAb2-A (i) reacted specifically with the immunizing anti-Id, (ii) were capable of binding VP7, (iii) inhibited M1875 from binding to VP7, and (iv) inhibited M1875 from binding to RAb2-A. Animals immunized with purified VP7 produced antibodies that possessed the epitope and idiotope specificity of M1875. No antibody responses to VP7 were detected in control animals immunized with either rabbit anti-Id to the pseudorabies virus glycoprotein gII or BHK-21 cell proteins. We conclude that rabbit anti-Id RAb2-A serologically mimics an M1875-defined VP7 epitope sufficiently to function as a surrogate antigen for inducing anti-bluetongue virus VP7 responses.

Study of Anti-Idiotype Antibodies to the Monoclonal Antibody HGT3a and its Relation to the 38 kDa Antigen of Mycobacterium tuberculosis

The hypervariable regions of the immunoglobulins which function as the antigen binding sites are capable of provoking an antibody response and are referred to as anti-idiotypic antibodies. Antisera were raised in rabbits against the idiotypes of a mouse monoclonal antibody HGT3a which binds only to the 38 kDa antigen of the M. tuberculosis complex group of organisms. Idiotype specificity in these antisera was determined by dot ELISA, Western blot and solid phase inhibition assays. In vivo administration of this rabbit anti-idiotypic antibody to Swiss mice evoked an anti-anti-idiotypic antibody response, further confirming the internal antigen mimicry by the anti-idiotypic antibodies of the 38 kDa antigenic epitope and its potential use as a surrogate antigen. Antibody response to the anti-idiotypic antibodies in the sera of patients with pulmonary tuberculosis showed significant correlation with the antibody response to the 38 kDa antigen studied in the same clinical samples indicating a close similarity of the 38 kDa antigen of M. tuberculosis and the rabbit andi-idiotypic antibody produced against MoAb HGT3a.

Production and characterization of rabbit anti-idiotypic antibodies directed against a murine monoclonal anti-B. abortus antibody.

The protective anti-beta abortus monoclonal antibody ISS/32 (Ab1) was used as an immunogen to induce anti-idiotypic antibodies (Ab2) in rabbits. The purpose was to produce and characterize anti-idiotypic antibodies that share conformational similarity with the corresponding bacterial epitope recognized by Ab1. The rabbit anti-IdAb so induced was isolated and affinity-purified. Its specificity for the paratope of Ab1 was determined by evaluating its ability to compete with B. abortus for binding to Ab1 in a competitive ELISA assay. The anti-idiotypic ISS/32 antibodies were able to compete with B. abortus for binding to Ab1 in a dose-dependent manner. Hence, the data indicated that the rabbit anti-Id ISS/32 antibodies reacted with or near the antigen-binding site of Ab1.

Identification of Protein-Receptor Components Required for the Import of Prealdehyde Dehydrogenase into Rat Liver Mitochondria

Mitochondrial aldehyde dehydrogenase is synthesized as a high-molecular-weight precursor in cytosol and transported into mitochondrial matrix space where it is processed to the mature enzyme. To identify components of the transport machinery on liver mitochondria, anti-idiotypic antibodies against the rabbit anti-prealdehyde dehydrogenase signal peptide antibodies were produced in chicken eggs and rabbit. Both anti-idiotypic antibodies inhibited the import of prealdehyde dehydrogenase (pALDH) into isolated rat liver mitochondria. The rabbit anti-idiotypic antibody could recognize by Western blotting five mitochondrial membrane proteins with apparent molecular weights of 66, 60, 42, 34, and 29 kDa. The anti-idiotypic antibodies were cross-linked to mitochondrial membrane proteins using sulfosuccinimidyl 2-(p-azidosalicylamido)ethyl-1,3′-dithiopropionate which is an iodinatable, heterofunctional, and photoreactive cross-linker. Mitochondrial proteins with apparent molecular weights of 66, 60, and 42 kDa were identified using the chicken antibody. The 66- and 34-kDa proteins were cross-linked to the rabbit antibody as the major components and the 42-kDa protein as a minor one. Antibodies against the 60- and 42-kDa proteins, as well as Fab fragments, inhibited the import of pALDH, suggesting that these proteins are receptor/translocator components for pALDH import.

Internal image rabbit anti-idiotypic antibody detects sheep antibodies to the bluetongue virus core protein VP7.

Rabbit polyclonal anti-idiotypic antibodies (anti-Id) were generated against three murine monoclonal antibodies (MAbs) specific for the group-specific antigen VP7 of bluetongue virus (BTV) by the sequential immunization method. It was demonstrated by serological tests that part of the anti-Id possesses the characteristics of internal image anti-Id. By affinity purification against the individual MAbs, the internal image anti-Id, designated RAb2-A, was isolated and identified as specific for the MAb, M1875. To examine the ability of RAb2-A to detect sheep anti-VP7 antibodies by recognition of the common idiotype (Idx). Affinity-purified RAb2-A IgG, along with VP7, was applied on the solid-phase of ELISA plate and the membrane for Western blot analysis to detect anti-VP7 antibodies from sheep that were immunized with VP7 or were experimentally infected with BTV. An inhibition ELISA was employed to determine whether sheep anti-VP7 and M1875 recognize the same or similar epitope(s). RAb2-A recognised the Idx on anti-VP7 antibodies from sheep that were either immunized with VP7 or experimentally infected with BTV. Specificity of the reaction was confirmed by the observation that RAb2-A did not react with normal sheep serum or sheep antibodies against epizootic haemorrhagic disease of deer virus, a bluetongue-related disease virus in the Orbivirus genus. The ability of RAb2-A to detect anti-VP7 antibodies through recognition of the Idx suggests that RAb2-A can be used as a probe to detect anti-BTV antibodies.

Rat antibodies bearing idiotypes of mouse antibodies against bromelain-treated mouse RBC.

Part of mouse antibodies reactive with bromelain-treated mouse RBC (BrMRBC) use VH12 and VK4 genes, and VH12/VK4-type antibodies are detectable specifically with rabbit anti-idiotype (Id) antibodies (here referred to as RAIb). This study showed that normal rat sera contained RAIb+ IgM at concentrations of 1-6 micrograms/ml. Rat spleens had many anti-BrMRBC B cells, most of which secreted RAIb+ IgM. Hybridomas of spleen cells from LPS-injected rats were screened with RAIb-binding and BrMRBC-hemolytic activity. We found 48 BrMRBC-hemolytic wells, which included all of 39 RAIb(+)-wells. From anti-BrMRBC wells, 7 RAIb+ monoclonal antibodies (mAb) were isolated. All the RAIb+ mAb could react with phospholipid antigens. Rat RAIb+ antibodies, as well as mouse RAIb+ antibodies, can be regarded as antiphospholipid antibodies reactive with BrMRBC. The interspecies expression of RAIb-Id on mouse and rat anti-BrMRBC antibodies indicates that some (antigenic) selective forces may act strongly to conserve the Id (V genes).

Signals through Membrane Ig of Peritoneal CD5 B Cells to Suppress LPS-Induced Ig Secretion

Murine peritoneal CD5 B cells include many B cells reactive with bromelain-treated mouse RBC (BrMRBC). Anti-BrMRBC B cells are thought to expand after selection by self-antigens, but little is known about signals through their membrane Ig (mIg). Most anti-BrMRBC antibodies use VH11 and Vk9 genes, and VH11/Vk9-type antibodies are detectable specifically with rabbit anti-idiotype antibodies (here referred to as RAIa). Preincubation of peritoneal cells with RAIa at 37°C before LPS stimulation reduced LPS-induced secretion of RAIn-detectable Ig. To render RAIn-reactive B cells hyporesponsive, a continuous reaction of their mIg with RAIa was necessary. Binding of BrMRBC to RAIa-reactive B cells hardly affected their LPS reactivity. It appears that fresh mIg deliver the suppressive signals after reacted with RAIa, and the degree of hyporesponsiveness of a RAIa-reactive B cell depends on the amount of mIg-RAIa complexes. RAIa-suppressed B cells could regenerate mIg in the absence of RAIa and could respond to LPS to enlarge. It is suggested that binding of RAIa to mIg renders RAIn-reactive B cells without proliferation in an anergy state, where synthesis of secretory Ig is rather specifically suppressed.

Protection of mice againstClostridium chauvoeiinfection by anti-idiotype antibody to a monoclonal antibody to flagella

Polyclonal rabbit anti-idiotypic antibody (anti-Id) against the protective monoclonal antibody specific to the flagella of Clostridium chauvoei was produced, purified, and characterized. Anti-Id inhibited the binding of its related monoclonal antibody to the flagellar antigen, suggesting that the anti-Id bore an internal image of the flagellar antigen. When mice were immunized with anti-Id intraperitoneally, the survival rate increased significantly, compared with mice immunized with normal rabbit IgG (P < 0.01), and specific anti-flagellar antibodies were induced.

Protection of mice against Clostridium chauvoei infection by anti-idiotype antibody to a monoclonal antibody to flagella

Polyclonal rabbit anti-idiotypic antibody (anti-Id) against the protective monoclonal antibody specific to the flagella of Clostridium chauvoei was produced, purified, and characterized. Anti-Id inhibited the binding of its related monoclonal antibody to the flagellar antigen, suggesting that the anti-Id bore an internal image of the flagellar antigen. When mice were immunized with anti-Id intraperitoneally, the survival rate increased significantly, compared with mice immunized with normal rabbit IgG (P < 0.01), and specific anti-flagellar antibodies were induced.

Antigenic mimicry of Clostridium chauvoei flagella by polyclonal anti-idiotypic antibodies.

Polyclonal rabbit anti-idiotypic (anti-Id) antibodies against two monoclonal antibodies (MAbs) specific for the flagella of Clostridium chauvoei were produced, purified and characterised. Lack of cross-reactivity with heterologous MAbs indicated that the anti-Id antibodies were highly specific. The surface-exposed epitopes of the flagellar filament recognised with protective MAb were further distinguished by the anti-Id antibodies. Moreover, each anti-Id antibody inhibited the binding of its related MAb to flagellar antigens in a competitive enzyme-linked immunosorbent assay, suggesting that the anti-Id antibodies bore an internal image of the flagellar antigens. The survival rate of mice was increased to nearly twice that of controls by immunisation with anti-Id 41, which had been produced with a protective MAb; in contrast, anti-Id 114, produced with a non-protective MAb, failed to immunise. The results suggest that an anti-Id antibody containing an internal image of C. chauvoei flagella might be used as a vaccine.