Dabhi V M, Hovik R, Van Kaer L, Lindahl K F
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235, USA.
J Immunol. 1998 Nov 15;161(10):5171-8.
MHC class Ib molecule H2-M3 presents N-formylated peptides to CD8+ CTLs. Endogenous formylated peptides can come from the N-terminus of each of the 13 proteins encoded by the mitochondrial genome. In peptide competition assays, two of these peptides bind with high affinity, six bind with intermediate affinity, three bind with low affinity, and two do not bind measurably. Alloreactive CTLs from M3-specific, mixed lymphocyte cultures responded strongly against the two peptides with high affinity for M3, occasionally to peptides with intermediate affinity, and not at all to the rest. Long term lines and CTL clones reacted with only the high affinity peptides, demonstrating that alloreactive CTLs depend on specific peptides and that peptide affinity for class I correlates with alloantigenicity.
MHC Ib类分子H2-M3将N-甲酰化肽呈递给CD8⁺CTL。内源性甲酰化肽可来自线粒体基因组编码的13种蛋白质中每一种的N端。在肽竞争试验中，其中两种肽以高亲和力结合，六种以中等亲和力结合，三种以低亲和力结合，两种未检测到结合。来自M3特异性混合淋巴细胞培养物的同种反应性CTL对与M3具有高亲和力的两种肽有强烈反应，偶尔对中等亲和力的肽有反应，对其余肽则无反应。长期细胞系和CTL克隆仅与高亲和力肽发生反应，表明同种反应性CTL依赖于特定肽，并且肽对I类的亲和力与同种抗原性相关。
