Self-recognition is crucial for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment.
The role of self-recognition in the maintenance of the peripheral CD4+ T-cell pool has been extensively studied, but no clear answer has so far emerged. Indeed, in studies of the role of self-major histocompatibility complex (MHC) molecules in CD4+ T-cell survival, several parameters must be taken into account when interpreting the results: (1) in a lymphopenic environment, observations are biased by concomitant proliferation of T cells arising in MHC-expressing mice; (2) the peripheral T-cell compartment is qualitatively and quantitatively different in nonlymphopenic, normal, and MHC class II-deficient mice; and (3) in C57BL/6 Abeta(-/-) mice (traditionally considered MHC class II-deficient), the Aalpha chain and the Ebeta chain associate to form a hybrid AalphaEbeta MHC class II molecule. In light of these considerations, we revisited the role of interactions with MHC class II molecules in the survival of peripheral CD4+ T cells. We found that the answer to the question "is self-recognition required for CD4+ T cells to survive?" is not a simple yes or no. Indeed, although long-term survival of CD4+ T cells does not depend on self-recognition in lymphopenic mice, interactions with MHC class II molecules are required for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment.
Martin
Bruno
B
Institut National de la Santé et de la Recherche Médicale (INSERM) U561, Saint-Vincent-de-Paul Hospital, Paris, France.
Bécourt
Chantal
C
Bienvenu
Boris
B
Lucas
Bruno
B
D000818:Animals; D001324:Autoantigens / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002470:Cell Survival / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout
D001324:Autoantigens; D000949:Histocompatibility Antigens Class II