B cells regulate expression of CD40 ligand on activated T cells by lowering the mRNA level and through the release of soluble CD40

Eur J Immunol. 1994 Apr;24(4):787-92. doi: 10.1002/eji.1830240402.


The expression of CD40 ligand (CD40L) on activated T cells (CD4+ T cell clone MT9) is diminished when the T cells are cultured in the presence of B cells. This effect, observed both with normal tonsil B cells and with the B cell line JY, was detected after 6 h and sustained at least until 18 h of co-culture. Analysis of mRNA showed that CD40L mRNA levels were not modified after 6 h, but were significantly down-regulated after 18 h of co-culture with B cells. Although CD40L expression could not be detected by a CD40-Fc chimera, the molecule was still expressed at the membrane as shown with a polyclonal antiserum against CD40L (anti-TRAP). In addition, T cells activated in the presence of B cells were stained by a polyclonal antiserum against CD40, without the appearance of CD40 mRNA. These results indicated that a soluble form of CD40 (sCD40) bound to the expressed CD40L on T cells. The existence of sCD40 was confirmed by detection of sCD40 in B cell supernatants using a specific enzyme-linked immunosorbent assay. Collectively, these data show that B cells can regulate the expression of CD40L on activated T cells at least by two different mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / metabolism*
  • Antigens, Differentiation, B-Lymphocyte / metabolism*
  • B-Lymphocytes / physiology*
  • CD40 Antigens
  • CD40 Ligand
  • Cells, Cultured
  • Down-Regulation
  • Humans
  • Lymphocyte Activation
  • Membrane Glycoproteins / analysis*
  • RNA, Messenger / analysis*
  • T-Lymphocytes / metabolism*


  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • CD40 Antigens
  • Membrane Glycoproteins
  • RNA, Messenger
  • CD40 Ligand