Jensen P E
Department of Pathology, Emory University, Atlanta, GA 30322, USA.
Semin Immunol. 1995 Dec;7(6):347-53. doi: 10.1006/smim.1995.0039.
CD4+ helper T cells recognize short peptides stably associated with class II MHC molecules displayed on the surface of antigen presenting cells. Very little is known about the sequence of events that lead to the generation of these peptides from protein antigens. It is likely that native proteins must partially unfold before they are cleaved by endopeptidases or bind to MHC proteins. For many antigens, the rate-limiting step in unfolding may involve reduction of disulfide bonds. Evidence that disulfide reduction occurs in endocytic compartments is reviewed and potential mechanisms for the reduction of antigen disulfide bonds are proposed.
CD4+辅助性T细胞识别与抗原呈递细胞表面所展示的II类主要组织相容性复合体（MHC）分子稳定结合的短肽。对于从蛋白质抗原产生这些肽的一系列事件的顺序，人们了解甚少。天然蛋白质很可能在被内肽酶切割或与MHC蛋白结合之前必须部分展开。对于许多抗原而言，展开过程中的限速步骤可能涉及二硫键的还原。本文综述了内吞小室中二硫键还原发生的证据，并提出了抗原二硫键还原的潜在机制。
