Characterization of a monoclonal antibody against P57, the C3/C3b-cleaving proteinase expressed in human erythrocyte membranes.
A monoclonal antibody was raised against p57, a serine proteinase, characterized by an apparent molecular weight of 57 kDa, and purified from human erythrocyte membranes. P57 proteinase cleaves the human third component of complement, C3. The antibody selected, MP1, of IgG2a isotype, precipitated specifically the p57 antigen which carried the C3/C3b-cleaving activity present in membrane crude extract of human erythrocytes. P57 proteinase eluted from MP1-sepharose was inhibited by 5 x 10(-4) M PMSF, enhanced by 0.5% SDS and generated C3 fragments identical to those generated by membrane crude extract of human erythrocytes. All these properties were identical to those of the p57 previously purified by biochemical procedures. In addition, 5000 binding sites were detected on cell surface. This MP1 monoclonal antibody will be helpful to analyse the role of p57 in human erythrocytes.
Immunochimie des Antigènes de Membrane et des Interactions Cellulaires, Centre I.N.S.E.R.M., Hôpital Saint-Antoine, Paris, France.
A
A
Fiandino-Tirel
M
M
Barel
F
F
Lyamani
A
A
Gauffre
J
J
Hermann
R
R
Frade
D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology; D000937:Antigen-Antibody Reactions; D003179:Complement C3b / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000737:chemistry*; D006801:Humans; D015151:Immunoblotting; D007525:Isoelectric Focusing; D008565:Membrane Proteins / Q000276:immunology / Q000302:isolation & purification*; D012697:Serine Endopeptidases / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D008565:Membrane Proteins; D003179:Complement C3b; D012697:Serine Endopeptidases; C050640:serine proteinase P-57