Characterization of monoclonal anti-alpha 1-microglobulin antibodies: binding strength, binding sites, and inhibition of lymphocyte stimulation

Research output: Contribution to journalArticle

Abstract

Eleven monoclonal antibodies (MoAb) directed against the immunoregulatory plasma glycoprotein alpha 1-microglobulin were characterized. The MoAb were produced in mice immunized with a mixture of alpha 1-microglobulin homologues from man, guinea pig, rat and rabbit. Using radioimmunoassay, western blotting, affinity chromatography, and Scatchard analysis, the affinities and binding sites of the MoAb were analysed. All antibodies were more or less cross-reactive, but most showed a major specificity for one or two of the alpha 1-microglobulin homologues. None of the antibodies was directed against the carbohydrate moiety of alpha 1-microglobulin. Six of the MoAb had high affinity for the antigen and four of these were directed towards the same part of the molecule though differing in their species specificity. Five showed lower affinity for the antigen and were mainly directed towards epitopes on other parts of the molecule. Only some of the antibodies could block the proliferation of lymphocytes induced by human alpha 1-microglobulin. The blocking efficiency of the different antibodies was similar when tested on the stimulation of human or mouse lymphocytes, suggesting that the same part of the alpha 1-microglobulin molecule is responsible in both species. The magnitude of blocking by the different MoAb was not related to their affinities, emphasizing the importance of where on the alpha 1-microglobulin molecule, rather than how strongly, they bind. The binding of the strongest blocking antibody was shown to be directed to a C-terminal peptide of rat alpha 1-microglobulin, indicating that this part of alpha 1-microglobulin is important for the mitogenic effects. Thus the panel of anti-alpha 1-microglobulin MoAb should be a valuable tool for structural and functional studies of alpha 1-microglobulin.

Details

Authors
Organisations
External organisations
  • Lund University
  • Sandoz Research Institute
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Immunology in the medical area

Keywords

  • Alpha-Globulins, Animals, Antibodies, Monoclonal, Antibody Affinity, Binding Sites, Antibody, Cross Reactions, Guinea Pigs, Humans, Lymphocyte Activation, Mice, Mice, Inbred BALB C, Peptide Fragments, Rabbits, Radioimmunoassay, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)655-666
Number of pages12
JournalScandinavian Journal of Immunology
Volume34
Issue number5
Publication statusPublished - 1991 Nov
Publication categoryResearch
Peer-reviewedYes