Production of IL-1-mimicking anti-idiotypic antibodies in rabbits in response to IL-1 immunization.
This report describes the characterization of immunoglobulins with interleukin-1 (IL-1)-like activity from the serum of rabbits immunized with partially purified mouse IL-1. Early after immunization, immune sera were found to contain anti-IL-1 antibodies (idiotypes) that inhibited IL-1 bioactivity (augmented-proliferation of PHA-stimulated thymocytes). Later, anti-idiotypic antibodies appeared that mimicked IL-1 activity. These IL-1-like antibodies were affinity purified either on an anti-IL-1-enriched Ig-Sepharose 4B column from an early bleed or sequentially on anti-Ig and Protein A immunoadsorbent columns. By ELISA anti-idiotypic antibodies specifically bound to rabbit anti-IL-1 antibodies. Functionally, IL-1 mimicking antibodies were reproducibly effective in augmenting the in vitro proliferation of PHA-stimulated thymocytes or Con A-stimulated D10 cells. On the other hand, they did not support proliferation of the IL-2-dependent CTLL-2 cells. The ability of IL-1-mimicking antibodies to enhance thymocyte proliferation could be blocked by functional site related anti-IL-1 antibodies. By Western blot, 125I-labeled IL-1 and IL-1-mimicking antibodies bound to a similar 23 Kd mol. wt protein material recovered from the lysate of thymocytes stimulated with PHA for 48 h. That the observed bioactivity could be attributed to antibody molecules and not to contaminant IL-1 was ascertained by several methods, namely (1) SDS-PAGE analysis of 125I-labeled material and (2) resistance to loss of bioactivity by lyophilization. Furthermore, as neither Ig-anti-Ig nor BSA-anti-BSA complexes mimicked IL-1-augmented thymocyte proliferation, a non-specific effect due to immune complexes could be excluded. The occurrence of antibodies mimicking several of the IL-1 functions induced following IL-1 immunization suggests a potential role for the idiotypic network in modulating cytokine activities and a possible link between regulation of the immune system by cytokines and immunoglobulin idiotypes.
Zuberi
R I
RI
Medical Biology Institute, La Jolla, CA 92037.
Katz
D H
DH
Zanetti
M
M
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis*; D000918:Antibody Specificity; D015153:Blotting, Western; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D007114:Immunization; D007130:Immunoglobulin Idiotypes / Q000032:analysis*; D007375:Interleukin-1 / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D011817:Rabbits
D000888:Antibodies, Anti-Idiotypic; D007130:Immunoglobulin Idiotypes; D007375:Interleukin-1