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Characterization of Monoclonal Anti‐α 1 ‐Microglobulin Antibodies: Binding Strength, Binding Sites, and Inhibition of Lymphocyte Stimulation
Author(s) -
BABIKERMOHAMED H.,
FORSBERG M.,
OLSSON M. L.,
WINQUIST O.,
NILSON B. H. K.,
LÖGDBERG L.,
AKERSTRÖM B.
Publication year - 1991
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1991.tb01589.x
Subject(s) - beta 2 microglobulin , monoclonal antibody , epitope , antibody , microbiology and biotechnology , chemistry , radioimmunoassay , antigen , biochemistry , stimulation , glycoprotein , biology , immunology , endocrinology
Eleven monoclonal antibodies (MoAb) directed against the immunoregulatory plasma glycoprotein α 1 ‐microglobulin were characterized. The MoAb were produced in mice immunized with a mixture of α 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, bul most showed a major specificity for one or two of the α 1 ‐ microglobulin homologues. None of the aniibodies was directed against the carbohydrate moiety of α 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 α 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 α 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 α 1 ‐microglobulin molecule, rather than how strongly, they bind. The binding of the strongest blocking antibody was shown lo be directed to a C‐terminal peptide of rat α 1 ‐microglobulin, indicating that this part of the α 1 ‐microglobulin is important for the mitogenic effects. Thus the panel of anti‐α 1 ‐microglobulin MoAb should be a valuable tool for structural and functional studies of α 1 ‐microglobulin.