LAG-3 is not responsible for selecting T helper cells in CD4-deficient mice.
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.
Miyazaki
T
T
Institut de Génétique et de Biologie Moléculaire et Cellulaire (CNRS/INSERM/ULP), Strasbourg, France.
Dierich
A
A
Benoist
C
C
Mathis
D
D
D000818:Animals; D015703:Antigens, CD; D015704:CD4 Antigens / Q000235:genetics*; D007153:Immunologic Deficiency Syndromes / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D000093322:Lymphocyte Activation Gene 3 Protein
D015703:Antigens, CD; D015704:CD4 Antigens; D008565:Membrane Proteins; D000093322:Lymphocyte Activation Gene 3 Protein; C000720327:Lag3 protein, mouse