title: CD4+ T cell survival is not directly linked to self-MHC-induced TCR signaling.
abstract: T cell receptor (TCR) signaling triggered by recognition of self-major histocompatibility complex (MHC) ligands has been proposed to maintain the viability of naïve T cells and to provoke their proliferation in T cell-deficient hosts. Consistent with this, the partially phosphorylated state of TCR zeta chains in naïve CD4+ and CD8+ T cells in vivo was found to be actively maintained by TCR interactions with specific peptide-containing MHC molecules. TCR ligand-dependent phosphorylation of TCR zeta was lost within one day of cell transfer into MHC-deficient hosts, yet the survival of transferred CD4+ lymphocytes was the same in recipients with or without MHC class II expression for one month. Thus, despite clear evidence for TCR signaling in nonactivated naïve T cells, these data argue against the concept that such signaling plays a predominant role in determining lymphocyte lifespan.
authors.affiliation: Lymphocyte Biology Section, Laboratory of Immunology, Building 10 Room 11N311, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Dorfman
authors.forename: I
authors.initials: I
authors.lastname: Stefanová
authors.forename: K
authors.initials: K
authors.lastname: Yasutomo
authors.forename: R N
authors.initials: RN
authors.lastname: Germain
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002470:Cell Survival / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008285:Major Histocompatibility Complex / Q000276:immunology*; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology*
chemical_list: D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain