Dabhi V M, Lindahl K F
Howard Hughes Medical Institute, Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9050, USA.
Eur J Immunol. 1998 Nov;28(11):3773-82. doi: 10.1002/(SICI)1521-4141(199811)28:11<3773::AID-IMMU3773>3.0.CO;2-B.
The MHC class Ib molecule H2-M3 presents N-formylated peptides from the N terminus of proteins encoded by the mitochondrial genome to CTL. A panel of CTL specific for a peptide derived from a mitochondrial protein, either COI or ND1, was used to determine the optimal peptide length for sensitizing antigen-deficient target cells. All long-term CTL lines and most CTL clones lysed target cells sensitized with either a COI hexamer or an ND1 heptamer. Only 3 out of 12 anti-ND1 clones preferred an octamer or nonamer peptide and no CTL required to longer peptides. The CTL preference for short peptides matches a shortened groove in M3. The CTL all lysed lymphoblasts encoding the appropriate mitochondrial antigen, suggesting that these target cells express naturally processed, endogenous, formylated peptides, ranging from six to nine amino acids in length.
MHC Ib类分子H2-M3将来自线粒体基因组编码蛋白质N端的N-甲酰化肽呈递给细胞毒性T淋巴细胞（CTL）。使用一组对源自线粒体蛋白（细胞色素氧化酶亚基I（COI）或NADH脱氢酶亚基1（ND1））的肽具有特异性的CTL，来确定使缺乏抗原的靶细胞致敏的最佳肽长度。所有长期CTL系和大多数CTL克隆都能裂解用COI六聚体或ND1七聚体致敏的靶细胞。12个抗ND1克隆中只有3个更喜欢八聚体或九聚体肽，没有CTL需要更长的肽。CTL对短肽的偏好与M3中缩短的肽槽相匹配。这些CTL都能裂解编码适当线粒体抗原的淋巴母细胞，这表明这些靶细胞表达天然加工的、内源性的、长度为6至9个氨基酸的甲酰化肽。
