Human CD40‐ligand: molecular cloning, cellular distribution and regulation of expression by factors controlling IgE production

Publisher Website
Google Scholar
Abstract
Here we report the cloning of the cDNA for human CD40‐Ligand (CD40‐L) from a CD4‐positive T cell clone. The deduced amino acid sequence predicts a type II membrane protein of 261 amino acids. Northern blot and FACS analysis of PBMNC revealed that the human CD40‐L can be detected on T cells and is absent from B cells and monocytes. The human CD40‐L is expressed on both CD4‐ and CD8‐positive T cells, (CD45RO+) and (CD45RA+) subsets. We observed that IL‐4, an inducer of IgE production, upregulated CD40‐L mRNA level while IFNy, an inhibitor of IgE synthesis, reduced the expression of CD40‐L mRNA. These data suggest a the correlation between human CD40‐L expression and IgE production.