MEM-59 monoclonal antibody detects a CD43 epitope involved in lymphocyte activation

Eur J Immunol. 1995 Apr;25(4):1051-5. doi: 10.1002/eji.1830250429.


Previous studies on T cell activation via CD43 antigen stimulation were limited to the use of L10, a monoclonal antibody (mAb) recognizing a sialic acid-independent epitope on the CD43 molecule. Here we study the CD43 mAb MEM-59, which recognizes a neuraminidase-sensitive epitope on the CD43 molecule, for its ability to activate T lymphocytes. The antibody by itself is able to stimulate proliferation of peripheral blood mononuclear cells (PBMC) in a monocyte-dependent fashion, and to act synergistically with the mitogen phorbol 12-myristate 13-acetate. It is demonstrated that the monocyte dependence of MEM-59-induced proliferation of peripheral blood lymphocytes (PBL) cannot be attributed to cross-linking via Fc receptors on monocytes alone: F(ab')2 fragments of MEM-59 are at least as effective as intact IgG in the induction of PBMC proliferation. The effects of MEM-59 reported here are distinct in important ways from those reported for L10. Our proliferation data are extended by the observation that MEM-59 mAb induces mobilization of intracellular Ca2+ in PBMC and in the T cell line Jurkat, while the CD3/TcR-negative Jurkat derived-mutant J.TR3-T3.5 exhibits defective signaling compared to the parent cell line. Moreover, CD3 and CD43 are shown to be present jointly in a large complex in a mild detergent lysate of the T cell line HPB-ALL. These data indicate a physical and functional association between CD3/TcR and CD43 pathways, suggesting a role for CD43 as a co-stimulatory molecule in CD3/TcR signaling, especially in T cell-antigen-presenting cell interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology
  • Antigens, CD*
  • Cell Division / drug effects
  • Epitopes / immunology
  • Humans
  • Leukocytes, Mononuclear / immunology
  • Leukosialin
  • Lymphocyte Activation / drug effects
  • Lymphocyte Activation / immunology*
  • Sialoglycoproteins / immunology*
  • T-Lymphocytes / immunology


  • Antibodies, Monoclonal
  • Antigens, CD
  • Epitopes
  • Leukosialin
  • SPN protein, human
  • Sialoglycoproteins