Monoclonal yeast killer toxin-like candidacidal anti-idiotypic antibodies.

Rat monoclonal yeast killer toxin (KT)-like immunoglobulin M (IgM) anti-idiotypic antibodies (KT-IdAbs) were produced by idiotypic vaccination with a mouse monoclonal antibody (MAb; MAb KT4) that neutralized a Pichia anomala KT characterized by a wide spectrum of antimicrobial activity. The characteristics of the KT-IdAbs were demonstrated by their capacity to compete with the KT to the idiotype of MAb KT4 and to interact with putative KT cell wall receptors (KTRs) of sensitive Candida albicans cells. The internal-image properties of KT-IdAbs were proven by their killer activity against KT-sensitive yeasts. This lethal effect was abolished by prior adsorption of KT-IdAbs with MAb KT4. These findings stressed the potential importance of antibody-mediated immunoprotection against candidiasis and suggested a feasible experimental approach for producing antimicrobial receptor antibodies without purifying the receptor. KT-IdAbs might represent the basis for producing engineered derivatives with a high potential for effective therapeutic antifungal activity.     

Monoclonal anti-idiotypic antibodies simulating the biological effects of human alpha-interferons]

The method of somatic hybridization was used to generate a panel of hybridomas producing monoclonal anti-idiotypic antibodies (mono-Ai-Ab) imitating biological effects of human alpha-interferons (hIF-alpha). Induction of syngeneic anti-idiotypic antibodies in BALB/c mice was achieved with monoclonal antibodies (MCA) IF-39 capable of neutralizing three kinds of hIF-alpha (lymphoblastoid, leukocyte, genetic-engineering). The screening of mono-Ai-Ab was done by determinations of antiviral activity (AV-activity) of supernatants from growing hybrid cell cultures caused by the cytopathic effect of 10-100 doses of mouse encephalomyocarditis virus (MEMC) by a micromethod in Vero cells grown in 96-well plates. Mono-Ai-Ab were found to neutralize MCA IF-39 and not to bind with immunosorbent of staphylococcal reagent containing protein A and BALB/c mouse immunoglobulins. It was shown that mono-Ai-Ab possessed AV-activity against MEMC and vesicular stomatitis viruses and were not inferior in this activity to commercial preparations of leukocyte IF-alpha. Mono-Ai-Ab had tissue species-specificity triggering the mechanism of AV-activity in human and simian cells as well as bovine kidney cells (MDVK line) imitating hIF-alpha in this effect.     

Monoclonal anti-idiotypic antibodies regulate the expression of virus-induced murine myocarditis.

A monoclonal anti-idiotypic antibody (anti-Id), produced by electrofusion and designated anti-Id88, was able to modulate expression of murine autoimmune myocarditis mediated by coxsackievirus B3 (CVB3). The anti-Id was characterized as an immunoglobulin G2b species possessing kappa light chains and was able to reduce expression of inflammatory myocarditis in anti-Id-pretreated mice challenged with CVB3. Anti-Id88 was able to stimulate specific cell-mediated immunity against anti-Id88, as well as CVB3, and exerted a suppressive effect on the proliferation of mixed spleen cell populations from virus-exposed mice. Anti-Id stimulated an anti-anti-Id antibody 3 population able to bind antibody 2 F(ab')2 fragments or virus antigen in an indirect enzyme-linked immunosorbent assay. Western blot (immunoblot) analysis of anti-Id88 exhibited binding of syngeneic anti-Id antibody to idiotypes present on immunoglobulin G molecules from virus-immunized mice.     

Monoclonal 'internal image' anti-idiotypic antibodies of hepatitis B surface antigen.

The hypervariable regions of the immunoglobulin molecule which function as the antigen-combining site are, themselves, capable of provoking an antibody response. These antigenic determinants on the immunoglobulin are termed the 'idiotype', and antibodies directed against them 'anti-idiotype'. In circumstances where there is a close complementarity of shape between antigen and idiotype, and subsequently between idiotype and anti-idiotype, it would be predicted that anti-idiotype would be like an 'internal image' of the antigen. Starting with a monoclonal antibody (idiotype) to the protective a determinant of the hepatitis B surface antigen (HBsAg), we have succeeded in raising two monoclonal anti-idiotypes which mimic HBsAg in their ability to bind polyclonal antibodies to HBsAg produced in a variety of species. These internal image anti-idiotypes may provide a strategy for immunization without the need for antigen.     

Monoclonal antibodies to the thyrotropin receptor

The thyrotropin receptor (TSHR) is a seven transmembrane G-protein linked glycoprotein expressed on the thyroid cell surface and which, under the regulation of TSH, controls the production and secretion of thyroid hormone from the thyroid gland. This membrane protein is also a major target antigen in the autoimmune thyroid diseases. In Graves' disease, autoantibodies to the TSHR (TSHR-Abs) stimulate the TSHR to produce thyroid hormone excessively. In autoimmune thyroid failure, some patients exhibit TSHR-Abs which block TSH action on the receptor. There have been many attempts to generate human stimulating TSHR-mAbs, but to date, only one pathologically relevant human stimulating TSHR-mAb has been isolated. Most mAbs to the TSHR have been derived from rodents immunized with TSHR antigen from bacteria or insect cells. These antigens lacked the native conformation of the TSHR and the resulting mAbs were exclusively blocking or neutral TSHR-mAbs. However, mAbs raised against intact native TSHR antigen have included stimulating mAbs. One such stimulating mAb has demonstrated a number of differences in its regulation of TSHR post-translational processing. These differences are likely to be reflective of TSHR-Abs seen in Graves' disease.     

Are spontaneous anti-idiotypic antibodies against anti-acetylcholine receptor antibodies present in myasthenia gravis?

The presence of anti-acetylcholine receptor anti-idiotypic antibodies in sera from 102 myasthenia gravis patients and from 33 first-degree relatives was investigated by: (a) Enzyme linked immunosorbent assay (ELISA) using monoclonal antibodies raised against human acetylcholine receptor, (b) immunoprecipitation of 125I-monoclonal anti-acetylcholine receptor antibodies; (c) inhibition of anti-acetylcholine receptor monoclonal antibody binding to the receptor and/or (d) inhibition of autologous and heterologous anti-acetylcholine receptor antibody binding to the receptor. No clear evidence for the presence of abnormal levels of spontaneous anti-idiotypic antibodies to anti-acetylcholine receptor antibodies was found.     

Monoclonal antibodies against the human interferon-gamma receptor(s)

Enriched human interferon-gamma (HuIFN-gamma) receptor preparations were obtained by affinity chromatography of non-ionic detergent solubilized COLO 205 cell membranes on immobilized recombinant HuIFN-gamma. The active fractions, identified by a competition ELISA, were used as the immunogen in a BALB/c mouse. Fusion of its splenocytes with myeloma cells yielded several hybrids secreting antibodies that inhibit the antiviral activity of HuIFN-gamma; the two most active ones were selected for further characterization. This blocking activity was restricted to both the human species and the gamma type of IFN. Affinity purification of cell membrane extracts on the immobilized monoclonal antibodies resulted in the visualization of a major protein band with an Mr of 90,000, which is in good agreement with the results obtained by other authors [Aguet M. and Merlin G. (1987) J. exp. Med. 165, 988-999; Novick D., Orchansky P., Revel M. and Rubinstein M. (1987) J. biol. Chem. 262, 8483-8487; Sheehan K. C. F., Calderon J. and Schreiber R. D. (1988) J. Immun. 140, 4231-4237].     

Monoclonal antibodies as probes of tetanus toxin structure and function

Monoclonal antibodies specific for fragment B, fragment C, and light chain of tetanus toxin were prepared by fusion of P3X63Ag8 BALB/c myeloma cells with spleen cells from BALB/c mice immunized with tetanus toxoid or fragment B. Hybridoma colonies were assayed for antibody production by an enzyme-linked immunosorbent assay. Fourteen positive clones were identified, cloned by limiting dilution, and injected intraperitoneally into mice to obtain ascites fluids. Thirteen of the monoclonal antibodies were of the immunoglobulin G1 subclass and one was immunoglobulin G2. Two of the antibodies were directed against sites on fragment C, nine were directed against the light chain, and three were directed against the portion of fragment B which does not comprise the light chain of tetanus toxin. At least one antibody in each group exhibited significant toxin neutralization activity. However, only one of these neutralizing antibodies strongly inhibited the binding of 125I-tetanus toxin to ganglioside-coated plates. These data indicate that interference with receptor recognition is not the only means of neutralizing tetanus toxin. Monoclonal antitoxins as potential therapeutic and prophylactic reagents are discussed.     

Monoclonal antibodies to somatostatin receptor of rat brain.

Murine Monoclonal antibodies (MAbs) to the rat brain somatostatin (SRIF) receptor were produced. Sp 2/0 myeloma cells were fused with splenocytes of Balb/c mice immunized with the soluble rat brain SRIF receptor which was partially purified by gel-filtration chromatography. Screening by radioligand ([125I-Tyr11]SRIF-14) binding inhibition assay yielded three stable cell lines producing IgG1, IgM, or IgA antibody. Autoradiographic study of the polyacrylamide gel electrophoresed under nondenaturing conditions revealed that these MAbs inhibited the ligand binding to the receptor, regardless of their incubation with the receptor prior to the ligand binding. The results suggest that the MAbs produced are the antibodies to the ligand binding site of the receptor, and bind to the receptor in competition with the ligand.     

Structural basis of stimulatory anti-idiotypic antibodies

In order to design and produce effective vaccines based upon the idiotype network hypothesis of Jerne, a thorough understanding of the biological and structural aspects underlying the stimulating activities of anti-idiotypic antibodies is needed. Here we determined the nucleotide sequence of the variable heavy and light chain regions of two monoclonal anti-idiotypic antibodies which induce different anti-phosphorylcholine responses. The nucleotide sequences of the variable domains of two monoclonal anti-TEPC 15 (T15) antibodies (F6-3 and 4C11) were determined by the primer extension and Maxam-Gilbert techniques. The nucleotide sequence data show that 4C11 and F6-3 have homologous VH segments and JH segments, but different D regions. The VH segments of both clones belongs to the J558 VH family. Most of the differences among the VH segments are located in CDR2. The VK segments of 4C11 and F6-3 are homologous to the VK gene group 4 and group 8, respectively. Comparison of the sequences of 4C11 and F6-3 with other published anti-idiotype antibodies shows that there is no preferential utilization of immunoglobulin genes. An analysis of the distribution of charged residues and hydropathic comparison studies were used to interpret the sequence of 4C11 in terms of the biological mimicry of antigenic stimulation.     

乙型肝炎表面抗体的抗独特型研究

用 HBsAg/a 决定簇的7A_4单克隆抗体(McAb_1)复合物,免疫同系 BALB/C 小鼠,制备了高效价抗独特型(Ab_2)血清和两株抗独特型 McAb(McAb_2).Ab_2血清和 McAb_2都能识别7A_4McAb_1的互补位独特型.Ab_2血清中有与异种(豚鼠、驴、兔和羊)抗—HBs 结合的抗体,两株 McAb 不能与异种抗-HBs结合的抗体,两株 McAb 不能与异种抗-HBs 结合,属非内影像 Ab_2γ.研究表明,HBsAg/a 决定簇的 McAb_1有不同的互补位,McAb_2可作为一种生物探针,用于区别 McAb_1的互补位.     

Idiotypes and anti-idiotypic antibodies: a review

An idiotype (Id), defined as an epitope within the variable region of immunoglobulin, is used as a structural and functional marker of the region. Anti-idiotypic antibodies (anti-Ids or Ab2s) can be generated upon immunization with an antibody (Ab1) which contains a variety of Ids. One set of anti-Ids, referred to as internal-image Ab2s, recognizes an Id which is shared by antibodies with the same or similar specificities. This Id is designated a common Id. Anti-Ids that recognize a common Id and represent an internal image of the antigen have been generated in many systems. Many experimental studies have shown the potentials of anti-Ids as immune regulators to various pathogens. The antigenic mimicry of internal-image Ab2β makes them valuable not only as immunogens for eliciting specific immune response to infectious pathogens but also as probes for studying cell receptors, as well as for immune therapy for tumors.     

Purification of immunoreactive radiolabeled monoclonal antibodies with anti-idiotypic monoclonal antibodies

A method is described to purify immunoreactive monoclonal antibodies from radiolabeled monoclonal antibody preparations. The method is based on incubation of radiolabeled monoclonal antibodies with insolubilized anti-idiotypic monoclonal antibodies to idiotopes within the antigen-combining site of monoclonal antibodies to be purified and elution of bound monoclonal antibodies with a low pH buffer. The immunoreactive fraction of the purified monoclonal antibodies was at least 82%; the yield was at least 73%. The purification procedure did not cause any detectable change in the affinity constant of the eluted monoclonal antibodies. The method is simple and rapid; the requirement for anti-idiotypic monoclonal antibodies to idiotopes within the antigen-combining site of the antibodies to be purified is not likely to represent a major limitation in the broad application of the present method, since the hybridoma technology has greatly facilitated the development of anti-idiotypic monoclonal antibodies.