Activated human T cells express a ligand for the human B cell-associated antigen CD40 which participates in T cell-dependent activation of B lymphocytes

Eur J Immunol. 1992 Oct;22(10):2573-8. doi: 10.1002/eji.1830221016.


To identify the ligand for the B cell-associated antigen CD40, we constructed a chimeric immunoglobulin molecule where the extracellular portion of the CD40 protein replaced the normal immunoglobulin variable region. No binding was detected on resting peripheral blood T cells. However, following T cell activation with phorbol esters and ionomycin, the chimeric protein bound specifically to activated human T cells and precipitated a 35-kDa protein from such cells. The induction of the CD40 ligand was detectable on the cell surface after 1 h, with maximal expression after 8 h of stimulation. The T cells expressing CD40 ligand were predominantly CD4 positive, although a proportion of CD8-positive cells also expressed the protein. There was no particular correlation with CD45 phenotype. Finally, we found that soluble CD40 inhibited T-dependent B cell proliferation. The results are discussed in the context of cognate interactions between B and T cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, CD / metabolism*
  • Antigens, Differentiation, B-Lymphocyte / metabolism*
  • B-Lymphocytes / immunology*
  • Base Sequence
  • CD3 Complex / physiology
  • CD40 Antigens
  • Humans
  • In Vitro Techniques
  • Lymphocyte Activation*
  • Molecular Sequence Data
  • Molecular Weight
  • Phenotype
  • Precipitin Tests
  • T-Lymphocytes / physiology*


  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • CD3 Complex
  • CD40 Antigens