Expression and functional characteristics of the complement receptor type 2 on adult and neonatal B lymphocytes

Clin Immunol Immunopathol. 1993 Oct;69(1):1-8. doi: 10.1006/clin.1993.1142.

Abstract

In vivo antibody synthesis against thymus-independent type 2 (TI-2) antigens such as type-specific polysaccharides of pneumococci is low or absent during the first 2 years of life. Recently, we described a role for CR2 in the in vitro antibody response of B cells of adults to the TI-2 antigen type 4 pneumococcal polysaccharide. In the present study a decreased expression of CR2 is described on cord blood B cells using HB5 and OKB7 anti-CR2 MAb. Crosslinking of HB5 anti-CR2 antibodies on the B cell membrane leads to increases in intracellular calcium ([Ca2+]i) in both adult and neonatal B cells. In adult B cells, a synergism between CR2 and sIgM could be demonstrated on the level of calcium mobilization by occupying CR2 and crosslinking of sIgM with substimulatory concentrations of anti-IgM antibodies. This synergistic action between CR2 and sIgM could not be demonstrated in neonatal B cells. In addition, it is demonstrated that HB5 MAb cannot induce B cell differentiation in neonatal B cells, while adult B cells can be induced to differentiate into Ig-producing cells by this MAb.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aging / blood*
  • Aging / immunology*
  • Antibodies, Monoclonal
  • Antibody Formation / immunology
  • Antigens, T-Independent / immunology
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / ultrastructure*
  • Calcium / blood
  • Cell Differentiation
  • Cell Membrane / physiology
  • Fetal Blood / cytology
  • Fetal Blood / immunology
  • Flow Cytometry
  • Humans
  • Immunoglobulin M / immunology
  • Indoles
  • Infant, Newborn
  • Lymphocyte Activation / immunology
  • Receptors, Complement 3d / physiology*
  • Signal Transduction / physiology

Substances

  • Antibodies, Monoclonal
  • Antigens, T-Independent
  • Immunoglobulin M
  • Indoles
  • Receptors, Complement 3d
  • indo-1
  • Calcium