Delon J, Grégoire C, Malissen B, Darche S, Lemaître F, Kourilsky P, Abastado J P, Trautmann A
Laboratoire d'Immunologie Cellulaire UMR CNRS 7627 CERVI, Paris, France.
Immunity. 1998 Oct;9(4):467-73. doi: 10.1016/s1074-7613(00)80630-5.
Physiologically, TCR signaling is unlikely to result from the cross-linking of TCR-CD3 complexes, given the low density of specific peptide-MHC complexes on antigen-presenting cells. We therefore have tested directly an alternative model for antigen recognition. We show that monomers of soluble peptide-MHC trigger Ca2+ responses in CD8alphabeta+ T cells. This response is not observed in CD8- T cells and when either the CD8:MHC or CD8:Lck interactions are prevented. This demonstrates that an intact CD8 coreceptor is necessary for effective TCR signaling in response to monomeric peptide-MHC molecules. We propose that this heterodimerization of TCR and CD8 by peptide-MHC corresponds to the physiological event normally involved during antigen-specific signal transduction.
从生理学角度来看，鉴于抗原呈递细胞上特异性肽 - 主要组织相容性复合体（pMHC）的低密度，T细胞受体（TCR）信号不太可能由TCR - CD3复合物的交联产生。因此，我们直接测试了一种抗原识别的替代模型。我们发现可溶性pMHC单体可触发CD8αβ⁺ T细胞中的Ca²⁺反应。在CD8⁻ T细胞中以及当CD8与MHC或CD8与淋巴细胞特异性蛋白酪氨酸激酶（Lck）的相互作用被阻断时，未观察到这种反应。这表明完整的CD8共受体对于响应单体pMHC分子的有效TCR信号传导是必需的。我们提出，肽 - MHC介导的TCR和CD8异二聚化对应于抗原特异性信号转导过程中通常涉及的生理事件。
