Ossendorp F, Eggers M, Neisig A, Ruppert T, Groettrup M, Sijts A, Mengedë E, Kloetzel P M, Neefjes J, Koszinowski U, Melief C
Department of Immunohematology, Academic Hospital Leiden, The Netherlands.
Immunity. 1996 Aug;5(2):115-24. doi: 10.1016/s1074-7613(00)80488-4.
CTL epitope (KSPWFTTL) encoded by AKV/MCF type of murine leukemia virus (MuLV) differs from the sequence in Friend/Moloney/Rauscher (FMR) type in one residue (RSPWFTTL). CTL experiments indicated defective processing of the FMR peptide in tumor cells. Proteasome-mediated digestion of AKV/MCF-type 26-mer peptides resulted in the early generation and higher levels of epitope-containing fragments than digestion of FMR-type peptides, explained by prominent cleavage next to R in the FMR sequence. The fragments were identified as 10- and 11-mer peptides and were efficiently translocated by TAP. The naturally presented AKV/MCF peptide is the 8-mer, indicating ER peptide trimming. In conclusion, a single residue exchange can cause CTL epitope destruction by specific proteasomal cleavage.
由AKV/MCF型鼠白血病病毒（MuLV）编码的CTL表位（KSPWFTTL）与Friend/Moloney/Rauscher（FMR）型的序列在一个残基上不同（RSPWFTTL）。CTL实验表明肿瘤细胞中FMR肽的加工存在缺陷。蛋白酶体介导的AKV/MCF型26聚体肽消化比FMR型肽消化产生表位含片段的时间更早且水平更高，这是由于FMR序列中R旁边的显著切割所致。这些片段被鉴定为10聚体和11聚体肽，并被TAP有效转运。天然呈现的AKV/MCF肽是8聚体，表明存在内质网肽修剪。总之，单个残基交换可通过特定的蛋白酶体切割导致CTL表位破坏。
