Expression of the CD40 ligand in T lymphocytes and induction of IgE isotype switching

Int Arch Allergy Immunol. May-Jun 1995;107(1-3):43-4. doi: 10.1159/000236925.


CD40 ligand (CD40L) delivers a contact-dependent signal to B cells which, in the presence of interleukin (IL)-4, drives immunoglobulin isotype switching to IgE. CD40L expression in T cells is transient, requires activation of protein kinase C and a rise in intracellular calcium concentration ([Ca2+]i), and is inhibited by cyclosporin A (CsA). CsA also inhibited T-cell-dependent IL-4-driven IgE synthesis. We have found that expression of CD40L is developmentally regulated. Expression of CD40L was restricted to mature single-positive thymocytes which, in the presence of IL-4, were capable of inducing B cells to undergo IgE isotype switching. CD40L expression was severely decreased in cord blood lymphocytes and was associated with a severely decreased ability to undergo T-cell-dependent IgE isotype switching.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Antigens, CD / physiology
  • Antigens, Differentiation, B-Lymphocyte / physiology
  • B-Lymphocytes / immunology
  • CD40 Antigens
  • CD40 Ligand
  • Cyclosporine / pharmacology
  • Fetal Blood / cytology
  • Gene Expression Regulation, Developmental*
  • Humans
  • Immunoglobulin Class Switching*
  • Immunoglobulin E / biosynthesis*
  • Infant, Newborn
  • Interleukin-4 / antagonists & inhibitors
  • Interleukin-4 / pharmacology
  • Lymphocyte Cooperation / drug effects
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / physiology
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*
  • Thymus Gland / cytology
  • Thymus Gland / growth & development


  • Antigens, CD
  • Antigens, Differentiation, B-Lymphocyte
  • CD40 Antigens
  • Membrane Glycoproteins
  • CD40 Ligand
  • Interleukin-4
  • Immunoglobulin E
  • Cyclosporine