细胞色素c
生物化学
细胞色素
化学
主要组织相容性复合体
生物
细胞生物学
基因
细胞凋亡
酶
作者
Philip A. Reay,Ronald M. Kantor,Mark M. Davis
出处
期刊:Journal of Immunology
[The American Association of Immunologists]
日期:1994-04-15
卷期号:152 (8): 3946-3957
被引量:184
标识
DOI:10.4049/jimmunol.152.8.3946
摘要
Substitution with all naturally occurring L-amino acids at each of 11 residues of the IEk-restricted month cytochrome c (93-103) epitope has allowed us to analyze the requirements for MHC binding and T cell recognition to a level of definition not previously possible. Substitutions at only three positions systematically affect MHC binding and three others appear to be the major TCR contacts. Interestingly, changing residues involved in MHC binding can ablate T cell recognition without altering MHC association. Additionally, residue identity at two positions that do not appear critical for MHC binding, nor to be involved in specific T cell contact, nonetheless dramatically affect T cell responses. This suggests that peptides differing only slightly in sequence can have significantly altered conformations within the class II MHC binding groove. We have also developed a simple scoring program that uses the binding data to quantitate how well a given peptide fits the MCC motif. All strongly immunogenic IEk-restricted epitopes score highly (> or = 0.70, where 1.0 is perfect concordance), and only 3% of all potential nonameric peptides in the two main protein sequence databases have scores greater than 0.70. This indicates that the global amino acid replacement approach using a single peptide is an efficient means of deriving binding motifs for a given class II MHC molecule, and should aid in the identification of novel T cell epitopes.
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