Expression of lymphocyte activation gene 3 (LAG-3) on B cells is induced by T cells

Eur J Immunol. 2005 Jul;35(7):2081-8. doi: 10.1002/eji.200526090.


Lymphocyte activation gene 3 (LAG-3/CD223) is a CD4 homolog known to be selectively expressed in activated T and NK cells. It is thought to have a negative regulatory function in T cells. With the help of new monoclonal antibodies against mouse LAG-3, we show that LAG-3 surface expression is not limited to activated T and NK cells but is also found on activated B cells. Induction of B cell surface expression is T cell dependent and mediated by a soluble factor. The majority of LAG-3 on B cell surface is endogenously produced, even though soluble LAG-3 is present in the culture supernatants and can be passively absorbed. As B cells express LAG-3 in a T cell dependent manner and not when activated by Toll-like-receptor agonists alone, we propose LAG-3 as a new marker of T cell induced B cell activation.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / analysis
  • Antigens, CD / genetics*
  • Antigens, CD / immunology
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / metabolism*
  • Cells, Cultured
  • Gene Expression Regulation / immunology*
  • Hybridomas
  • Lymphocyte Activation / genetics*
  • Lymphocyte Activation / immunology
  • Lymphocyte Activation Gene 3 Protein
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Rats
  • Rats, Inbred Lew
  • Signal Transduction / immunology*
  • Spleen / immunology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism*


  • Antibodies, Monoclonal
  • Antigens, CD
  • Lymphocyte Activation Gene 3 Protein