Unusually high frequency of Epstein-Barr virus genetic variants in Papua New Guinea that can escape cytotoxic T-cell recognition: implications for virus evolution.

摘要: Cytotoxic T lymphocytes (CTLs) which recognize viral antigens in association with human leukocyte (HLAs) play an important role controlling persistent virus infections. These viruses use several mechanisms to evade the immune response, including mutations that affect either T-cell receptor recognition or binding of epitopes HLA. It has recently been proposed distribution HLA frequencies and specific CTL response may influence long-term evolution Epstein-Barr (EBV) by selecting variants lack immunodominant epitopes. To test this hypothesis, we have studied EBV isolates from two genetically distinct Papua New Guinea (PNG) populations, residing coastal highland regions, for polymorphism within seven epitope sequences restricted through class I HLAs. Surprisingly, all analyzed displayed identical amino acid substitutions A11-, B35- B8-restricted completely abrogated synthetic peptides molecules. Furthermore, these revealed no correlation contemporary HLAs different PNG argues a minimal pressure. The sequence homology between suggests had single origin and, more importantly, are those present Caucasian population.