title: MHC class II deprivation impairs CD4 T cell motility and responsiveness to antigen-bearing dendritic cells in vivo.
abstract: The role continuous contact with self-peptide/MHC molecules (self ligands) in the periphery plays in the function of mature T cells remains unclear. Here, we elucidate a role for MHC class II molecules in T cell trafficking and antigen responsiveness in vivo. We find that naïve CD4 T cells deprived of MHC class II molecules demonstrate a progressive and profound defect in motility (measured by real-time two-photon imaging) and that these cells have a decreased ability to interact with limiting numbers of cognate antigen-bearing dendritic cells, but they do not demonstrate a defect in their responsiveness to direct stimulation with anti-CD3 monoclonal antibody. Using GST fusion proteins, we show that MHC class II availability promotes basal activation of Rap1 and Rac1 but does not alter the basal activity of Ras. We propose that tonic T cell receptor signaling from self-ligand stimulation is required to maintain a basal state of activation of small guanosine triphosphatases critical for normal T cell motility and that T cell motility is critical for the antigen receptivity of naïve CD4 T cells. These studies suggest a role for continuous self-ligand stimulation in the periphery for the maintenance and function of mature naïve CD4 T cells.
authors: Center for Immunology and Department of Pediatrics, University of Minnesota, 312 Church Street SE, Minneapolis, MN 55455, USA.
authors: Ursula B
authors: UB
authors: Fischer
authors: Erica L
authors: EL
authors: Jacovetty
authors: Ricardo B
authors: RB
authors: Medeiros
authors: Brian D
authors: BD
authors: Goudy
authors: Traci
authors: T
authors: Zell
authors: Jeannie-Beth
authors: JB
authors: Swanson
authors: Elizabeth
authors: E
authors: Lorenz
authors: Yoji
authors: Y
authors: Shimizu
authors: Mark J
authors: MJ
authors: Miller
authors: Alexander
authors: A
authors: Khoruts
authors: Elizabeth
authors: E
authors: Ingulli
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology*; D002450:Cell Communication; D002465:Cell Movement; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology; D051379:Mice; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
chemical_list: D000939:Epitopes; D000949:Histocompatibility Antigens Class II; D020830:rac1 GTP-Binding Protein; D020827:rap1 GTP-Binding Proteins; D018631:ras Proteins