Idiotypic expression of anti-gp120 antibodies in unrelated human immunodeficiency virus-infected individuals.
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Although it is recognized that human immunodeficiency virus (HIV) env genes exhibit a high degree of variability, little is known about the molecular heterogeneity of gp120-specific antibodies in infected individuals. As a first step to approach this issue, we investigated the idiotypic relatedness of anti-gp120 antibodies present in the serum of HIV-infected individuals. Idiotypic determinants (idiotopes) are fingerprints of the variable region of the antibody molecule and, as such, they represent unique probes with which to explore the diversity of the immune response. We isolated IgG anti-gp120 antibodies from the serum of a seropositive asymptomatic individual by affinity chromatography. The purified antibodies were shown to bind gp120 and gp160 by ELISA, Western blotting and radio-immunoprecipitation. They also recognized HIV-infected human T cells as detected by immunofluorescence. Anti-idiotypic reagents were generated against this gp120 idiotype, and one of them was used to study anti-gp120 idiotypic diversity in a panel of 65 sera drawn from AIDS and AIDS-related complex patients, and from HIV seropositive asymptomatic individuals. Sixty normal human sera were used as negative controls. We found no evidence for common idiotopes on anti-gp120 antibodies of unrelated individuals. In contrast, we also noticed that the idiotypic profile expressed sequentially at two different intervals in a persistently infected individual showed little variation. Finally, when the diversity of murine anti-gp120 antibodies with a monoclonal anti-idiotype was analysed, no evidence of cross-reactive idiotopes in the murine system was found. (+info)
Down-regulation of a spontaneous arthritis in male DBA/1 mice after administration of monoclonal anti-idiotypic antibodies to a cross-reactive idiotope on anti-collagen antibodies.
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We recently described a spontaneously occurring, inflammatory and erosive joint disease in male DBA/1 mice. A major question is whether specific immune reactions are involved in eliciting this disease. The possibility that collagen autoimmunity might constitute one pathogenic factor was particularly interesting as this spontaneous arthritis appears to be genetically restricted in a way similar to collagen-induced arthritis. In the present study, we demonstrate increased serum antibody levels to collagen II in a fraction of the male DBA/1 mice, but not in age-matched female controls. Administration of antibodies with an anti-idiotypic activity to anti-collagen II antibodies and with an affinity for determinants present on isolated syngeneic IgG Fc but not on intact IgG, was shown to interfere with the development of the spontaneous arthritis in a manner similar to that earlier documented for collagen arthritis. These observations suggest that mechanisms similar to those operating in collagen-induced arthritis may also be found in the spontaneously occurring arthritis in male DBA/1 mice. (+info)
Characterization of the cDNA of a broadly reactive neutralizing human anti-gp120 monoclonal antibody.
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The F105 mAb, identified in an HIV-1-infected individual, binds to a discontinuous epitope on the HIV-1 gp120 envelope glycoprotein, blocks the binding of gp120 to the CD4 viral receptor, and neutralizes a broad range of HIV-1 isolates. This study reports the primary nucleotide and deduced amino acid sequences of the rearranged heavy and light chains of the mAb F105. This IgG1k mAb uses a VH gene member of the VH4 gene family (V71-4) and is productively rearranged with a D-D fusion product of the dlr4 and da4 germline DH genes and the JH5 gene. This rearranged heavy chain gene expresses the VH4-HV2a idiotope, which is seen in human monoclonal IgM cold agglutinins. The F105 Vk appears to be derived from the Humvk325 germline gene and is rearranged with a Jk2 gene. For both chains, the mutational pattern in the rearranged VH and VL genes is indicative of an antigen-driven process. These studies show that production of a broadly neutralizing anti-HIV-1 antibody that recognizes determinants within the CD4 recognition site of the envelope glycoprotein is achieved by rearrangement of the V71-4 and Humvk325 germline variable region genes along with selected individual point mutations in the rearranged genes. (+info)
Immunoglobulin (Ig) mu, kappa transgenic mice express transgenic idiotype on endogenously rearranged IgM and IgA molecules by secretion of chimeric molecules.
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The sera of C57BL/6 mice transgenic for a mu a allotype heavy (H) chain and kappa light chain gene contained endogenous nontransgene immunoglobulin (IgM) (mu b allotype) and IgA molecules which carried the idiotype expressed by the transgenically encoded IgM (mu a) molecule. Serological analysis demonstrated that the presence of the transgenic idiotype on endogenous IgM and IgA was caused by the secretion of chimeric molecules that carried both chains encoded by the mu a transgene and products of endogenously rearranged Ig mu b or alpha genes. These and other results suggest that allelic exclusion of Ig gene rearrangement in mu, kappa transgenic mice is not absolute, that B cells can secrete Igs composed of more than a single (H) chain type, and that endogenous isotype switching does not result in a complete silencing of transgene expression. (+info)
Induction of immune responses in patients with B-cell lymphoma against the surface-immunoglobulin idiotype expressed by their tumors.
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BACKGROUND: The idiotypic determinants of the surface immunoglobulin of a B-cell lymphoma can serve as a clonal tumor-specific marker, which may have implications for immunotherapy. We sought to determine whether idiotype-specific immune responses against this autologous antigen could be induced in patients with B-cell lymphoma. METHODS: Nine patients were selected who had minimal residual disease or a complete remission after chemotherapy. Each received a series of subcutaneous injections of the immunoglobulin derived from his or her tumor cells (immunoglobulin-idiotype protein), which had been conjugated to a protein carrier and mixed with an immunologic adjuvant. RESULTS: In seven of the nine patients the injections induced sustained idiotype-specific immunologic responses of the humoral type (two patients), the cell-mediated type (four patients), or both (one patient). The use of an adjuvant was essential for these immune responses. The induced antibodies bound specifically to autologous immunoglobulin idiotype, inhibited the binding of murine monoclonal antiidiotype antibodies, and bound autologous tumor cells. Cell-mediated responses were demonstrated by the specific proliferation of immune peripheral-blood mononuclear cells to the soluble immunoglobulin-idiotype protein in vitro. The tumors of both of the patients with measurable disease regressed completely. Toxicity associated with the vaccine was minimal and consisted only of mild reactions at the site of intramuscular injection. CONCLUSIONS: These results demonstrate that autologous immunoglobulin idiotype can be formulated into an immunogenic, tumor-specific antigen in humans with B-cell lymphoma, and they provide the background for large-scale trials of active specific immunotherapy of this disease. (+info)
Documentation of idiotypic cascade after Lym-1 radioimmunotherapy in a patient with non-Hodgkin's lymphoma: basis for extended survival?
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PURPOSE: The purpose of this study was to examine idiotypic cascade mechanisms in the plasma of a prolonged survivor patient with aggressive non-Hodgkin's lymphoma (NHL). It is a follow-up to previously published seminal studies by this laboratory showing survival benefit associated with radioimmunotherapy in NHL patients. Immunoglobulin from the patient's plasma was purified, characterized, and shown to possess the activities expected of idiotypic antibodies. EXPERIMENTAL DESIGN: Plasma from a NHL patient treated with Lym-1 was precipitated with ammonium sulfate and octanoic acid, followed by immunoadsorbant chromatography with solid phase Lym-1 monoclonal antibody to purify Ab2. The last purification step involved the binding of Ab3 to glutaraldehyde-fixed Raji cells, followed by acid elution of Ab3. Proteins were quantified and characterized. Antibody-dependent cellular cytotoxicity activity was determined using a standard (51)Cr release assay. RESULTS: Purified immunoglobulin populations exhibited the characteristics of Ab2beta and Ab3 antibodies. Both showed ability to compete with the binding of Lym-1 to its tumor cell target, and Ab3 showed ability to induce antibody-dependent cellular cytotoxicity. CONCLUSIONS: This study offers direct evidence for initiation of a multilevel idiotypic cascade in a patient undergoing passive monoclonal antibody therapy for NHL. The patient's prolonged disease-free survival may, thus, be understood in the context of the generation of endogenous, self-perpetuating tumor-specific antibodies. (+info)
Idiotype vaccination of multiple myeloma patients using monocyte-derived dendritic cells.
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BACKGROUND AND OBJECTIVES: Dendritic cells (DC) pulsed with multiple myeloma (MM) patient-specific idiotype (Id) protein can induce MM-specific T-cell responses. DESIGN AND METHODS: We established serum-free culture conditions to generate monocyte-derived DC for clinical use to circumvent anti-xenogenic immune responses with repetitive vaccinations. In a clinical phase I trial twelve patients responsive to high dose chemotherapy (HDT) were vaccinated with autologous Id pulsed DC vaccines followed by Id/keyhole limpet hemocyanin (Id/KLH) booster immunizations co-injected with granulocyte-macrophage colony-stimulating factor as adjuvant. RESULTS: In vitro studies showed that serum-free-generated DC were equally effective in the induction of specific T-cell responses as were DC generated with fetal calf serum. On average 4.5 x 10(6) DC of >60% purity were generated from peripheral blood monocytes obtained 3-6 months after HDT and autologous stem cell transplantation. Ten of twelve patients received all planned vaccines without serious toxicity. Two patients developed Id-specific T-cell proliferative responses, in one patient an Id-specific cytotoxic T lymphocyte (CTL) response was measured. Id-specific TH1 cytokine secretion was found in one of the T-cell responding patients. All patients who received at least three Id/KLH vaccines mounted strong KLH specific T-cell and delayed antibody responses. Two patients remain in clinical partial response at 25 and 29 months after the start of the vaccination and ten patients have progressed, six of whom have died from progressive disease or infectious complications. INTERPRETATION AND CONCLUSIONS: Serum-free DC vaccines induce Id-specific T-cell responses in MM patients. (+info)
Autoantibodies against cyclophilin in systemic lupus erythematosus and Lyme disease.
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Autoantibodies against cyclophilin, a cyclosporin A binding protein, were detected in sera of 29 of 46 (63%) patients with systemic lupus erythematosus and 14 of 40 (35%) Lyme disease patients. The antibodies are directed against the denatured form of both the major and minor isoform of cyclophilin and can be demonstrated in Western blots. Some first-degree relatives of lupus patients also express these antibodies. They are specific for cyclophilin and are not the consequence of hypergammaglobulinaemia. Four monoclonal IgM antibodies from a patient with lepromatous leprosy also bound to cyclophilin. The generation of these antibodies may be of special interest because they are against a protein involved in the control of the immune system not known to be directly associated with DNA or RNA. (+info)