TAP-independent MHC class I peptide antigen presentation to alloreactive CTL is enhanced by target cell incubation at subphysiologic temperatures.

摘要: We investigated the peptide dependency of a group CD8 + anti-HLA-B7 alloreactive CTL. The CTL killed target cells after acid denaturation more than 98% cell surface peptide/MHC class I complexes. also TAP − HLA-B7 -transfected T2 (T2B7) cells. killing was enhanced by incubation at 26°C. Despite these findings, which suggested peptide-independent allorecognition, CTL-mediated cytolysis reduced or abolished several point mutations affecting peptide-binding groove. Acid HLA complexes on T2B7 prohibited recognition. recognition restored with β 2 -microglobulin and single HPLC fraction containing peptides extracted from cells, but not any panel 17 synthetic HLA-B7-binding peptides. These findings indicated that allorecognition specific. Sensitizing only amount detected in least 10-fold 100-fold greater incubated 26°C 37°C, respectively. TAP-independent epitope presentation sensitive to treatment brefeldin A, chloroquine, consistent an endogenous source. propose subphysiologic temperature can enhance total absence function.