Regulation of T-cell functions by MHC class II self-presentation.
The role of MHC class II in the control of T-cell responses to self and foreign antigens is still unclear. No unifying principle yet explains how class II molecules repress immunity to self or allogeneic antigens. Our recent data in a model of tolerance to allogeneic grafts, probably induced by allele-specific class II peptides, suggest that it is by presenting themselves [class II peptide(s) docked on self class II, in a complex we have named T-Lo] that class II controls T-cell activity. The engagement of the regulatory T (T-reg)-cell T-cell receptor (TCR) with self T-Lo would explain the beneficial effect of donor-recipient class II matching in clinical transplantation, the correlation between T-cell suppression and class II, and the altered T-reg-cell functions observed in class II-dependent autoimmune pathologies.
LeGuern
Christian
C
Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Building 149-9019, Boston, MA 02129, USA. Leguern@helix.mgh.harvard.edu
D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D018448:Models, Immunological; D008969:Molecular Sequence Data; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000949:Histocompatibility Antigens Class II