Monovalent ligands of complement receptor 2 inhibit whereas polyvalent ligands enhance anti-Ig-induced human B cell intracytoplasmic free calcium concentration

J Immunol. 1990 Mar 1;144(5):1640-5.


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 [Ca2+] in indo-loaded B cells, immediately after exposure to anti-mu 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). Anti-CR2 antibody HB5, tetravalent P13, and P28 conjugated to BSA, enhanced the ability of F(ab')2 fragments of the IgG fraction of goat anti-human mu antibody to increase human B cell [Ca2+]i. In contrast, the monomeric CR2 ligands C3d and P28 inhibited the anti-mu-induced increase in human B cell [Ca2+]i. Multivalent P13, P28, and the HB5, by themselves, did not affect B cell [Ca2+]i. These experiments suggest that the valence of the CR2 ligands is crucial for the nature (synergistic vs antagonistic) of the message transmitted through the CR2.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antigens, Differentiation, B-Lymphocyte / physiology
  • B-Lymphocytes / physiology*
  • Calcium / physiology*
  • Humans
  • In Vitro Techniques
  • Ligands
  • Lymphocyte Activation*
  • Receptor Aggregation
  • Receptors, Antigen, B-Cell / physiology*
  • Receptors, Complement / physiology*
  • Receptors, Complement 3d
  • Signal Transduction


  • Antigens, Differentiation, B-Lymphocyte
  • Ligands
  • Receptors, Antigen, B-Cell
  • Receptors, Complement
  • Receptors, Complement 3d
  • Calcium