Sweetser M T, Morrison L A, Braciale V L, Braciale T J
Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.
Nature. 1989 Nov 9;342(6246):180-2. doi: 10.1038/342180a0.
Class I and class II MHC-restricted T lymphocytes recognize non-native forms of antigen. The presentation of antigen to these two classes of T lymphocytes can occur through distinct pathways. Several mechanisms, including differences in antigen processing in different intracellular compartments, have been proposed to account for these pathway differences. Here we describe a T-cell epitope located on the influenza virus haemaglutinin, which is recognized by both class I and class II MHC-restricted cytolytic T lymphocytes (CTL). When expressed de novo in target cells, from a synthetic minigene encoding only the epitope, this pre-processed antigenic site is recognized by class I but not class II MHC-restricted T lymphocytes, even though target cells treated with the exogenously introduced peptide can be recognized by both classes of T cells. Because endogenous expression of the pre-processed antigenic fragment results in differential presentation to class I and class II MHC-restricted CTL, differences between the two different pathways of presentation could lie not at the level of processing but at the level of targeting and/or interaction of processed antigen with MHC.
I类和II类主要组织相容性复合体（MHC）限制性T淋巴细胞识别非天然形式的抗原。抗原呈递给这两类T淋巴细胞可通过不同途径发生。已经提出了几种机制，包括不同细胞内区室中抗原加工的差异，来解释这些途径差异。在这里，我们描述了位于流感病毒血凝素上的一个T细胞表位，它被I类和II类MHC限制性细胞毒性T淋巴细胞（CTL）识别。当从仅编码该表位的合成小基因在靶细胞中从头表达时，这个预先加工的抗原位点被I类而不是II类MHC限制性T淋巴细胞识别，尽管用外源引入的肽处理的靶细胞可被这两类T细胞识别。因为预先加工的抗原片段的内源性表达导致对I类和II类MHC限制性CTL的不同呈递，所以两种不同呈递途径之间的差异可能不在于加工水平，而在于加工抗原与MHC的靶向和/或相互作用水平。
