The nature of the peptide/MHC ligand involved in positive selection.
Positive and negative selection in the thymus occur when the TCR on an immature thymocyte engages self peptide/MHC complexes present on epithelial cells. The signaling mechanism which dictates the selection outcome is currently a matter of intense investigation. Here we review experiments that defined the peptide ligands for positive selection. A comparison of these to the peptide ligands that induce negative selection (antigenic peptides) sheds some insight into how a thymocyte interprets peptide/MHC interactions leading to life versus death of the cell.
Hogquist
K A
KA
Department of Lab Medicine and Pathology, University of Minnesota, Minneapolis 55455, USA.
Bevan
M J
MJ
D000818:Animals; D006801:Humans; D008024:Ligands; D008285:Major Histocompatibility Complex / Q000276:immunology*; D010455:Peptides / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
D008024:Ligands; D010455:Peptides