LeGuern Christian
Transplantation Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Building 149-9019, Boston, MA 02129, USA.
Trends Immunol. 2003 Dec;24(12):633-8. doi: 10.1016/j.it.2003.10.010.
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.
MHC II类分子在控制T细胞对自身和外来抗原的反应中的作用仍不清楚。目前尚无统一的原理来解释II类分子如何抑制对自身或同种异体抗原的免疫反应。我们最近在同种异体移植物耐受模型中的数据，可能由等位基因特异性II类肽诱导产生，表明II类分子通过呈递自身（停靠在自身II类分子上的II类肽，存在于我们命名为T-Lo的复合物中）来控制T细胞活性。调节性T（T-reg）细胞的T细胞受体（TCR）与自身T-Lo的结合，将解释供体-受体II类分子匹配在临床移植中的有益作用、T细胞抑制与II类分子之间的相关性，以及在II类分子依赖性自身免疫性疾病中观察到的T-reg细胞功能改变。
