Mouse Monoclonal Anti-idiotypic Antibody Research Articles

Virus-inhibitory activity of the antigen complex of opportunistic pathogenic bacteria against SARS-CoV-2

Introduction. The antigen complex of opportunistic pathogenic bacteria (ACOPB) has a protective effect against avian influenza viruses, herpes virus type 2, and other viruses that cause acute respiratory viral infections. In the context of the COVID-19 pandemic, an important task is to find out whether ACOPB has a protective effect against SARS-CoV-2.
 The purpose of the study was to evaluate in vitro the ACOPB virus-inhibitory activity against the Dubrovka laboratory strain of SARS-CoV-2.
 Materials and methods. The study was performed using Vero cell line CCL-81, human peripheral blood mononuclear cells (PBMCs), mouse monoclonal anti-idiotypic antibodies structurally mimicking biological effects of human interferons (IFNs), the Dubrovka laboratory strain of SARS-CoV-2. The infectivity of the virus was assessed by two methods: by virus titration using cell cultures and the limiting dilution method when the results are assessed by a cytopathic effect; the second method was a plaque assay. The in vitro virus inhibition test was performed using the cell culture susceptible to SARS-CoV-2; the mixture containing a specific dose of the virus and a two-fold dilution of ACOPB was transferred to the cell culture after the ACOPB medication had interacted with the virus at 4C for 2 hours. The ACOPB virus-inhibitory activity against SARS-CoV-2 was assessed by the functional activity of / and IFN receptors (RIFN) in human PBMCs induced in vitro by ACOPB and the ACOPB mixture with the specific dose of SARS-CoV-2. The RIFN expression level was measured by the indirect membrane immunofluorescence test.
 Results. Hemagglutination assay using chicken, mouse, guinea pig, and human red blood cells was performed for detection of the SARS-CoV-2 inhibitory protein. The lysate of Vero CCL-81 cells infected with SARS-CoV-2 Dubrovka demonstrated the highest hemagglutination activity with guinea pig red blood cells and low titers of hemagglutination in the virus-containing fluid. The virus inhibition test in the Vero CCL-81 cell culture demonstrated that ACOPB inhibited 10 doses of SARS-CoV-2 Dubrovka with the titer 1 : 32, providing 100% protection of the cell culture for 8 days (the monitoring period). ACOPB induced / and RIFN expression on membranes of human PBMCs in in vitro cultures and decreased RIFN / and expression after its interaction with SARS-CoV-2 Dubrovka.
 Conclusion. The experimental studies including the virus inhibition test in the cell culture susceptible to SARS-CoV-2 Dubrovka and the indirect membrane immunofluorescence assay using monoclonal anti-idiotypic antibodies mimicking IFN-like properties demonstrated that ACOPB had both an immunomodulatory and a virus-inhibitory effect.

A human monoclonal IgM with autoantibody activities against heparan sulphate and the mitotic spindle

A monoclonal IgM kappa from a patient with Waldenström's macroglobulinaemia (IgM-Rod) was found to react at temperatures below 28 degrees C with all tissue basement membranes and the cell coat of non-haematopoietic cells. IgM-Rod antibody was directed against heparan sulphate side chains of heparan sulphate proteoglycans as shown by binding in a solid-phase ELISA to heparan sulphate glycosaminoglycans but not to other purified subcomponents of the extracellular matrix; and by specific inhibition of the observed reactivity by heparitinase treatment. IgM-Rod showed cross-reactivity by indirect immunofluorescence with an as yet unidentified structure expressed in the nucleus during cell division and becoming associated with the mitotic spindle apparatus. The co-existence of both binding activities for heparan sulphate and nuclei determinants in the same IgM molecule was deduced from adsorption-elution experiments and from the inhibitory effect of a mouse monoclonal anti-idiotypic antibody directed against the paratope of IgM-Rod.

Neutrophil Priming by Cigarette Smoke Condensate and a Tobacco Anti-Idiotypic Antibody

A polyphenol-rich reagent, referred to as CSC, was isolated from cigarette smoke condensate and shown to prime purified human neutrophils. A mouse monoclonal anti-idiotypic antibody directed against the polyphenol-reactive determinants on a rabbit polyclonal anti-tobacco glycoprotein antibody was generated and shown to also prime neutrophils. After priming by CSC or tobacco anti-idiotypic antibody, there was a 2.5-fold to threefold increase in CD11b/18 expression and doubling of the number of formyl-methionyl-leucyl-phenylalanine receptors on the cells. The primed cells showed a twofold increase, compared with unprimed cells, in production of superoxide and release of neutrophil elastase after stimulation with formyl-methionyl-leucyl-phenylalanine. Neutrophils in peripheral blood of cigarette smokers have been shown to be primed and more responsive to activating agents. The priming effects attributed to whole cigarette smoke have been demonstrated in these studies using purified neutrophils and CSC or tobacco anti-idiotypic antibody. These studies are a first step in testing the hypothesis that the inflammatory process contributing to progression of chronic obstructive pulmonary disease in ex-smokers may be driven, in part, by tobacco anti-idiotypic antibodies. This hypothesis is novel and carries with it the implication of a heretofore unrecognized autoimmune component in the disease process manifested through production of anti-idiotypic antibodies with tobacco-like activity.

Monoclonal antiidiotypic antibodies neutralize cytotoxic effects of anti-alphaGal antibodies.

The aims of this study were to produce and characterize mouse monoclonal antiidiotypic antibodies (AIAs) that specifically bind human antipig (anti-alphaGal) antibodies and to select those AIAs that neutralize the cytotoxicity of human or baboon serum to pig (PK15) cells. Mice were immunized with human anti-pig antibodies, and hybridomas were produced using conventional techniques. From a total of 480 clones, 11 produced AIAs that bound with high affinity to human anti-alpha Gal IgG and F(ab')2 fragments, and individually reduced serum cytotoxicity to pig cells by 40 - 90%. Seven of the AIAs also bound to human peripheral B lymphocytes (that express the same idiotypes as the antibodies produce). Several combinations of two or three AIAs provided 100% protection of PK15 cells. Selected AIAs injected intravenously into baboons reduced the cytotoxicity of subsequently drawn sera by 50--80% for >48 hr. The cytotoxicity studies also indicated that there are at least two dominant idiotypes expressed in the human anti-alphaGal population. We conclude that AIAs against anti-alphaGal antibodies could be successfully used in 1) preoperative characterization of a recipient's anti-alphaGal profile, (2) prevention of hyperacute rejection of a pig organ, and (3) specific immunosuppression through elimination of anti-alphaGal-producing B lymphocytes.

Production of mouse monoclonal anti-idiotypic antibodies specific to epitopes of tumor-associated mucin TAG-12.

The tumor-associated mucin-glycoprotein TAG-12 is strongly expressed in approximately 96% of all breast cancer patients and nearly 68% of all ovarian cancers. The experimental results of this work indicated that humoral immune response against TAG-12 is possible. Immunization with anti-idiotypic monoclonal antibodies produces this response. In this experiment, anti-idiotypic monoclonal antibodies represent the internal image of a specific epitope on TAG-12. Monoclonal antibody (MAb) 12H12 was selected to produce anti-idiotypic antibodies (anti-Ids) because of its high reactivity with TAG-12. Syngeneic murine anti-Ids were developed by immunization of BALB/c mice with the 12H12-Fab-KLH conjugate. A competitive assay with purified TAG-12 was utilized to identify anti-Ids with mirror image function. Two MAbs with "internal image" specificity were selected, 5H8 and 5H2. Two New Zealand White rabbits were immunized with 5H8. Serum samples tested 6 weeks after the initial immunization showed comparable titers against TAG-12. The binding capacities of the rabbit sera to different human breast as well as nonbreast cancer cell lines demonstrated strong binding with TAG-12-positive breast cancer cell lines. Competitive inhibition assays demonstrate that Ab3 and purified TAG-12 totally inhibit the binding of 12H12 antibody to TAG-12-positive cells. No inhibition was detectable with unrelated MAbs or normal mouse immunoglobulin. Binding assays with polyclonal Ab3 serum and several human cancer cell lines showed reactivity to nearly every tested cell line. Soluble TAG-12 showed no inhibition, indicating that this binding is due to a different set of idiotypes. Anti-Id 5H8 elicited an immune response to TAG-12. Utilization of anti-Id as a vaccine against the breast cancer-associated tumor antigen TAG-12 was successfully demonstrated in a xenogeneic animal model.

Differentiation of human lambda I variable regions with a monoclonal antibody to a defined, germ-line-encoded idiotope correlates with V lambda Ia chemical structure.

This article describes the characterization of a mouse monoclonal anti-idiotypic antibody (1H7B) prepared against a human monoclonal rheumatoid factor (RFSJ2) whose L chain utilized a V lambda I subgroup gene. The mAb 1H7B reacted with 6 of the tested 12 human V lambda I proteins, as well as with a newly produced lambda mAb whose V lambda gene usage has not as yet been determined. Because six of the 1H7B-positive mAb were heterogeneous with respect to both their VH gene utilization and antigenic specificity, and because mAb 1H7B did not react with any of the tested 43 kappa or 12 lambda proteins belonging to various subgroups other than V lambda I, mAb 1H7B appeared to be a V lambda I subgroup-specific reagent. The L chain specificity of mAb 1H7B was confirmed by Western blotting, and the inhibition of RFSJ2 binding to human Fc gamma by 1H7B provided additional evidence for the V region specificity of mAb 1H7B. The 11 sequenced V lambda I proteins used in this study were assigned to sub-subgroups by comparison with the previously published germ-line V lambda Ia, V lambda Ib, and V lambda Ic sequences. The mAb 1H7B only appeared to recognize V lambda Ia proteins as it reacted with five of the seven V lambda Ia, but not with three V lambda Ib or with one V lambda Ic protein. Because mAb 1H7B reacted with at least one V lambda Ia sequence in germ-line configuration, it appeared to be a marker for V lambda Ia sub-subgroup germ-line gene(s). The idiotope recognized by 1H7B was localized to the first framework region by inhibiting its binding to RFSJ2 with a synthetic peptide to the 11-24 amino acid region of V lambda Ia L chains. Comparison of the V lambda 1-24 region sequence of RFSJ2 with those of the two 1H7B-negative V lambda Ia mAb revealed a single amino acid difference at position 17, suggesting that the idiotope recognized by 1H7B encompassed this position.

Mouse monoclonal anti-idiotypic antibodies to HIV p24: Immunochemical properties and internal imagery

Two mouse monoclonal antibodies (VIC5 and VIC6; referred to as Ab1) reacting with the p24 core antigen of HIV-1 were used to produce mouse monoclonal anti-idiotypic antibodies (Ab2). Six anti-idiotypic antibodies were characterized. The five anti-idiotypic antibodies directed against VIC6 partly competed which each other and thus defined a set of overlapping idiotypes on Ab1. All 6 Ab2s inhibited the binding of the corresponding anti-p24 antibody to antigen, although four (W1, Y16, Y6, X14) were markedly more inhibitory than the remaining two (G6, Y11). All six Ab2s were antigen-inhibitable; however the interaction of G6 and Y11 with Ab1 was blocked with considerably less soluble p24 antigen than the remaining four. Correspondingly, G6 and Y11 had lower affinities for Ab1 than did Wl, Y6 and X14; the affinity index of Y16 was equivalent to that of Y11. None of the Ab2s reacted with H or L chains of Ab1 after reduction on SDS-gels. Similarly, both Abls failed to react with the H or L chains of Ab2. These criteria appeared to define at least four of these Ab2s as internal image antibodies whose image is composed of both H and L chains. The anti-idiotypic antibodies were injected either individually or as a combined preparation of all 6 into syngeneic mice and Porton rats. Despite the presence of anti-anti-idiotypic antibodies (Ab3) in these animals, when used individually no antigen-specific antibodies were found. A small response to p24 antigen was induced in 3 of 6 mice using preparations containing all 6 anti-idiotypes.

Generation and characterization of an anti-idiotypic antibody specific for intercellular adhesion molecule-1.

Intercellular adhesion molecule-1 (ICAM-1) is an inducible ligand for the LFA-1/MAC-1 family of leukocyte adhesion molecules. The results reported herein show that a mouse monoclonal anti-idiotypic antibody, CA3, specific for R6.5 anti-ICAM-1 mAb, shares conformational homology with the original epitope bound by R6.5. The CA3 bound specifically to R6.5 F(ab) fragments and blocked the binding of R6.5 to its ICAM-1 epitope; no CA3 binding was detected to a second anti-ICAM-1 mAb F(ab) fragment nor to control mouse IgG F(ab) fragments. Similarly, the interaction of CA3 with R6.5 was inhibited by sICAM-1. However, CA3 was ineffective in inhibiting CD18-dependent cell aggregation. A rabbit anti-CA3 response (Ab3) further indicated that CA3 is of the Ab2 beta type. Significant binding of anti-CA3 to sICAM-1 was demonstrated and anti-CA3 competed with R6.5 for binding to sICAM-1. Anti-CA3 bound to both soluble and cell-surface-associated ICAM-1. However, unlike R6.5, significant binding both to reduced sICAM-1 and to native sICAM-1 was exhibited by anti-CA3, whereas the binding of R6.5 to reduced sICAM-1 was undetectable.

Induction, via immunization with a monoclonal antiidiotypic antibody, of viral envelope specific Ab3 antisera that neutralize retrovirus infectivity.

We have developed five mouse monoclonal antiidiotypic antibodies to the 35/56 (Ab1) rat monoclonal that neutralizes retroviral infectivity by binding to the gp70f epitope of murine leukemia retrovirus. The anti-Id nature of these five Ab2s was evidenced by their inability to react with a panel of six other rat IgG2a kappa monoclonals isotype-matched to the 35/56 anti-gp70f mAb1, including two to the distinct epitopes "g" and "h" of gp70, or to normal rat IgG2a. On the basis of several competition assays four mAb2 were clearly either directed to the paratope of anti-gp70f mAb1 (.1C7, .1B, and .E) or not (.A, representing a noninternal image Ab2 alpha anti-Id). The P3E8 mAb2 was difficult to classify. Based on relative efficiency in these assays, .1C7 was chosen for further study, and upon injection was able to induce Ab3 responses in C57BL/6, BALB/c, and CBA mice. The fact that the Ab3 activity was detected in a competitive ELISA in which the hyperimmune antisera blocked the binding of Ab1 to Ab2, plus the ability to raise Ab3 neutralizing antibodies in three different mouse strains were consistent with .1C7 as an internal image Ab2 beta anti-Id. These results thus indicate the potential for internal-image monoclonal antiidiotypic antibody-based vaccines for retroviral diseases.

Variable region cDNA sequences of three mouse monoclonal anti-idiotypic antibodies specific for anti-α(1→6)dextrans with groove- or cavity-type combining sites

The variable regions of three syngeneic anti-idiotypic antibodies (Ab2s) were cloned and sequenced. They are encoded by different V L genes, two are from different members of Vg-Ox1 superfamily. The H chains are encoded by V H genes belonging to three different V H families, J558, Q52 and 7183. Together with a previous report from this laboratory, the nucleotide sequences of four Ab2s to anti-α(1→6)dextrans have been presented. They are derived from a number of unrelated germline genes, and differ from similar studies in anti-NP, anti-GAT and anti-Ars systems. Three of four Ab2s in the anti-α(1→6)dextran system appear to have D-D fusions, which has also been reported in several other Ab2s.

Identification and immunochemical characterization of IgA in sera of patients with mammary tumors

It has been reported that several types of human cancer are associated with elevated levels of class-A immunoglobulins (Ig) and IgA-containing immune complexes. Moreover, most previous work has come up against the lack of IgA reactivity for chemically defined antigen (Ag). To overcome this, we first evaluated possible immunological binding in sera of patients with mammary tumors or malignant hematologic diseases and controls on a mouse monoclonal anti-idiotypic antibody (Ab2), internal image of conjugated benzo(a)pyrene (BP) coated on well plates. Using this indirect ELISA, a statistically highly significant immunological binding was found in sera of patients with mammary tumors of every grade, type and size. This immunological binding was linked to the IgA isotype. Second, we performed competition experiments between a BP conjugate coated on well-plates and anti-anti-"BP-like" antibodies (Ab) previously incubated with rabbit idiotypic antibodies (Ab1) directed against conjugated BP. A part of these anti-anti-BP-like Ab, raised in rabbits immunized with human IgA of patients with mammary tumors, recognized the Ag-combining site of polyclonal Ab1, previously developed in a rabbit immunized with BP conjugates. It appears that part of the human Ig from sera of patients with mammary tumors shares common idiotopes with rabbit polyclonal Ab1 raised against conjugated BP.

Characterization of private and cross-reactive idiotypes associated with human antibodies to hepatitis B surface antigen.

Four mouse monoclonal anti-idiotypic antibodies (anti-Id) were generated against human monoclonal and polyclonal antibodies to hepatitis B surface antigen (HBsAg). These monoclonal anti-Id, along with a polyclonal anti-Id raised in rabbits, were used to characterize the idiotype (Id) specificity of the human antibody response to HBsAg (anti-HBs). The anti-Id reagents identified distinct private and cross-reactive Id expressed on monoclonal and polyclonal human anti-HBs preparations respectively. The anti-Id recognized both HBsAg combining site and non-combining site related private Id, and HBsAg combining site related cross-reactive Id. The Id specificities recognized by two of the monoclonal anti-Id were associated with the H chain alone, whereas two of the monoclonal anti-Id, along with the polyclonal anti-Id appeared to recognize Id determinants associated with both isolated H and L chains. These data suggest that Id heterogeneity exists within the human antibody response to HBsAg. The knowledge that Id heterogeneity exists is of importance in understanding the observed variability in the immune response during hepatitis B virus infection.

Monoclonal anti-idiotypic antibody to progesterone with internal image properties

An auto-anti-idiotypic approach was used to generate mouse monoclonal anti-idiotypic antibody E9F11F6 (Ab2) to progesterone. A conjugate of 4-pregnane 3,20 dione and bovine serum albumin was used as the immunogen. E9F11F6 bound to a rabbit anti-progesterone antibody in a linear concentration-dependent manner. It inhibited the binding of [3H]progesterone to a monoclonal anti-progesterone antibody, E9D5 (Ab1); this inhibition was concentration dependent. Results from chase experiments showed that this inhibitory activity of Ab2 was not due to steric hindrance but was a result of direct binding to the ligand combining site. Indirect immunofluorescence studies also showed that Ab2 and progesterone bound to similar binding sites on Ab1. Overall, the results suggest that E9F11F6 contains an internal image of at least part of the progesterone molecule, and that it can be classified as an Ab2 beta antibody. This anti-idiotypic antibody may be of value in further studies of endocrine and reproductive physiology.

A Murine Monoclonal Anti-Idiotypic Antibody Detects a Common Idiotope on Human, Mouse and Rabbit Antibodies to Allergen Lol p IV

A syngeneic mouse monoclonal anti-idiotypic antibody (anti-Id), designated as B1/1, was generated against a monoclonal antibody (MoAb 91) specific for Ryegrass pollen allergen Lol p IV. This anti-Id recognized an idiotope (Id) that was also present on other monoclonal antibodies with the same specificity as MoAb 91. Observations that (i) the anti-Id inhibited the binding of MoAb 91 to Lol p IV and (ii) the Id-anti-Id interaction could be inhibited by Lol p IV indicated that the Id was located within or near the antigen combining site. These properties served to characterize B1/1 as an internal image anti-Id. Evidence that an immune response in different species to Lol p IV elicits the formation of antibodies which express a common Id was provided by the observations that (i) the Id-anti-Id interactions could be inhibited by mouse, human and rabbit antisera to Lol p IV and (ii) the binding of these antisera to Lol p IV could be inhibited by the anti-Id. Interestingly, the internal image anti-Id B1/1 also recognized an Id on a monoclonal antibody which was directed to an epitope of Lol p IV, different from that recognized by MoAb 91.

Anti‐idiotypic antibodies specific for a pathologic anti‐Pr2 cold agglutinin

The heterogeneity of human red cell (RBC) autoantibodies may be assessed by using anti-idiotypic antibodies. In this study, mouse monoclonal anti-idiotypic antibodies were produced against a pathologic RBC autoantibody with anti-Pr2 specificity. Epstein-Barr virus-transformed B-cell clones were established from a patient who had splenic lymphoma and associated immune hemolysis due to an anti-Pr2 cold autoantibody. Two of the eight clones producing this autoantibody were used to immunize mice for the establishment of hybridomas, and four monoclonal anti-idiotypic antibodies were isolated (2 IgG1 kappa and 2 IgM kappa). By the use of these anti-idiotypic antibodies, strong crossreactivity was seen on enzyme-linked immunosorbent assay with other anti-Pr2-producing clones from the same patient, but no cross-reactivity was seen with RBC autoantibodies from other individuals having anti-Pr or different specificities. Each of the anti-idiotypic antibodies inhibited hemagglutination (HA) by the patient's anti-Pr2 but failed to inhibit HA by antisera of a different RBC specificity. Cross-competition experiments indicated that all of the anti-idiotypic antibodies may recognize the same or a closely related idiotope on the anti-Pr2 autoantibody. These studies suggested that the four anti-idiotypic antibodies are directed against the same (or closely related) idiotypic determinant(s), unique to this patient's anti-Pr2 and located at or near the antigen-binding site. These anti-idiotypic antibodies may be useful tools for the study of this autoimmune response or for the development of immune therapeutic agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of Cross-Reactive Idiotypes in the Serum of Patients with Bullous Pemphigoid

To further characterize the circulating antibasement membrane zone (antiBMZ) antibodies present in the sera of patients with bullous pemphigoid (BP), we have generated a mouse monoclonal anti-idiotypic antibody (antiId 3-17) specific for an IgG antiBMZ antibody. AntiId 3-17 is specific for an idiotype expressed on antiBMZ IgG in the serum of a patient with BP, and not expressed on pooled normal human IgG or IgG from patients with other autoimmune skin diseases. AntiId 3-17 binds to non-reduced, but not reduced, antiBMZ IgG on immunoblot, suggesting that the idiotype is composed of a conformational epitope expressed on native antibody. By a competitive inhibition ELISA, antiId 3-17 detects a cross-reactive idiotype (CRI) expressed in 18 of 50 (36%) of the sera of patients with BP, but in the sera of only 1 of 50 (2%) normal blood bank controls (p less than 0.001, Fisher's exact test) and 1 of 12 (8%) patients with pemphigus (p = 0.005). Thus, antiId 3-17 recognizes a public idiotype on a native antiBMZ antibody from a patient with BP, which is expressed in the sera of 36% of the unrelated patients with BP studied.

Administration of noninternal image monoclonal anti-idiotypic antibodies induces idiotype-restricted responses specific for human immunodeficiency virus envelope glycoprotein epitopes

A mouse monoclonal anti-idiotypic antibody (anti-Id), designated MCI, was generated against chimpanzee antibodies specific for a synthetic peptide corresponding to a native epitope associated with gp41 of human immunodeficiency virus (HIV). This anti-Id recognized a shared idiotope/idiotype (Id) on a second chimpanzee anti-gp41 peptide preparation but failed to detect this Id on rabbit and mouse anti-gp41 peptide antibodies induced by immunization with the gp41 synthetic peptide. The chimpanzee Id-MC1 reaction was not inhibited by either synthetic peptide or recombinant gp160 suggesting that MCI exhibits noninternal image, Ab-2a-like characteristics. Immunization of syngeneic Balb/c mice with MCI induced an antigen-positive (Ag +) response capable of binding the synthetic peptide, recombinant gp160, and gp41, whereas MCI-immunized rabbits did not produce any detectable anti-peptide and/or anti-HIV envelope glycoprotein antibody response. The MC1-induced anti-Id response (Ab-3) in both mice and rabbits expressed a similar Id with the Ab-1, which is not normally expressed in the anti-gp41 peptide antibody response induced by the nominal antigen in Balb/c mice and in rabbits. Together, these studies indicate that a mouse monoclonal anti-ld of the Ab-2α class can induce an anti-HIV response specific for a gp41 epitope defined by a synthetic peptide, which does not cross species barriers.

Induction of experimental systemic lupus erythematosus in mice by immunization with a monoclonal anti-La autoantibody

Experimental systemic lupus erythematosus (SLE) in mice can be induced by immunization either with a human monoclonal anti-DNA antibody bearing the 16/6 idiotype (16/6 Id) or with a mouse monoclonal anti-idiotypic antibody specific for the 16/6 Id. In the present report we investigated the pathogenic role of a monoclonal anti-La autoantibody in the induction and mediation of experimental SLE in mice. The monoclonal anti-La antibody was derived from a mouse in which experimental SLE was induced by immunization with the monoclonal anti-16/6 Id antibody. Following immunization with the anti-La antibody the mice produced antibodies to double-stranded DNA, single-stranded DNA, Sm, SS-A/Ro, SS-B/La, and ribonucleoprotein. Furthermore, even though the anti-La antibody does not express nor react with the 16/6 Id, the immunized mice produced high titers of anti-16/6 Id antibodies as well as 16/6 Id bearing antibodies. Four months following immunization the mice exhibited significant proteinuria, and kidney sections revealed immune complex deposits on the basement membrane of the glomeruli. These results suggest that anti-La autoantibodies are involved in the induction and mediation of SLE in mice.

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.

The influence of monoclonal antibodies against human spermatozoa on the penetration rate of human spermatozoa in the zona-pellucida-free hamster-oocyte system

A mouse monoclonal anti-idiotypic antibody (anti-Id), designated MCI, was generated against chimpanzee antibodies specific for a synthetic peptide corresponding to a native epitope associated with gp41 of human immunodeficiency virus (HIV). This anti-Id recognized a shared idiotope/idiotype (Id) on a second chimpanzee anti-gp41 peptide preparation but failed to detect this Id on rabbit and mouse anti-gp41 peptide antibodies induced by immunization with the gp41 synthetic peptide. The chimpanzee Id-MC1 reaction was not inhibited by either synthetic peptide or recombinant gp160 suggesting that MCI exhibits noninternal image, Ab-2a-like characteristics. Immunization of syngeneic Balb/c mice with MCI induced an antigen-positive (Ag+) response capable of binding the synthetic peptide, recombinant gp160, and gp41, whereas MCI-immunized rabbits did not produce any detectable anti-peptide and/or anti-HIV envelope glycoprotein antibody response. The MC1-induced anti-Id response (Ab-3) in both mice and rabbits expressed a similar Id with the Ab-1, which is not normally expressed in the anti-gp41 peptide antibody response induced by the nominal antigen in Balb/c mice and in rabbits. Together, these studies indicate that a mouse monoclonal anti-ld of the Ab-2α class can induce an anti-HIV response specific for a gp41 epitope defined by a synthetic peptide, which does not cross species barriers.