Monovalent Ligands of Complement Receptor 2 Inhibit Whereas Polyvalent Ligands Enhance Anti-Ig-Induced Human B Cell Intracytoplasmic Free Calcium Concentration.

摘要

We have performed experiments to investigate the role of ligands for complement receptor 2 (CR2) in human B cell activation. Flow microfluorimetry was used to assess changes in free intracytoplasmic calcium concentration Ca(2+) in indo-loaded B cells, immediately after exposure to anti-micron antibody and to monovalent or polyvalent CR2 ligands. As monovalent ligands we used the C3d fragment and synthetic C3 peptides (peptides P14, residues 1201-1214, and P28, residues 1187-1214). As polyvalent ligands we used i) an intact monoclonal mouse anti-CR2 antibody (HB5) and its F(ab'2) fragment, ii) tetravalent P13 ((residues 1202-1214) 4-template), and iii) P28 conjugated to BSA (molar ratio 5/1). B cell, Complement receptor 2, Antigen receptor, Cell calcium. (EG)