LAG-3 is not responsible for selecting T helper cells in CD4-deficient mice

Int Immunol. 1996 May;8(5):725-9. doi: 10.1093/intimm/8.5.725.


The product of the LAG-3 gene is a cell surface protein with significant homology to CD4. It has been suggested that it can serve as a functional equivalent of CD4 and account for the MHC class II-restricted responses which persist in CD4-deficient mice. To test this hypothesis, we have created CD4/LAG-3 double-deficient mice by successive homologous recombinations in embryonic stem cells. These animals turn out to be indistinguishable from CD4 single-deficient mice in their lymphocyte populations and responses that are controlled by MHC class II molecules. LAG-3 thus does not explain class II-restricted lymphocyte selection and function in the absence of CD4, strengthening the idea that these phenomena can occur independently of co-receptor signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD*
  • CD4 Antigens / genetics*
  • Immunologic Deficiency Syndromes / genetics
  • Immunologic Deficiency Syndromes / immunology
  • Lymphocyte Activation / genetics*
  • Lymphocyte Activation Gene 3 Protein
  • Membrane Proteins / genetics*
  • Membrane Proteins / immunology
  • Membrane Proteins / physiology*
  • Mice
  • Mice, Knockout
  • T-Lymphocytes, Helper-Inducer / immunology*


  • Antigens, CD
  • CD4 Antigens
  • Membrane Proteins
  • Lymphocyte Activation Gene 3 Protein
  • Lag3 protein, mouse