Pfeifer J D, Wick M J, Roberts R L, Findlay K, Normark S J, Harding C V
Department of Pathology, Washington University School of Medicine, St Louis, Missouri 63110.
Nature. 1993 Jan 28;361(6410):359-62. doi: 10.1038/361359a0.
Class I major histocompatibility complex (MHC) molecules present antigens that are produced within the presenting cell or penetrate from the vacuolar system into the cytosol for processing. Most studies of exogenous antigen processing have used soluble antigens, which are not efficiently presented by class I MHC molecules and do not elicit CD8 T-cell responses in vivo. But particulate antigen preparations with no known mechanism for cytosolic penetration can also elicit CD8 T-cell responses in vivo. We report here that phagocytosis of bacteria with no mechanism for cytosolic penetration also results in presentation of bacterial antigens by class I MHC molecules. Moreover, this mechanism is resistant to cycloheximide and Brefeldin A, which block the classical class I processing pathway. These results suggest a novel vacuolar class I processing pathway for exogenous phagocytic antigens.
I类主要组织相容性复合体（MHC）分子呈递在呈递细胞内产生的抗原，或从液泡系统穿透进入胞质溶胶进行加工的抗原。大多数关于外源性抗原加工的研究使用的是可溶性抗原，这类抗原不能被I类MHC分子有效呈递，且在体内不会引发CD8 T细胞反应。但没有已知胞质穿透机制的颗粒性抗原制剂在体内也能引发CD8 T细胞反应。我们在此报告，没有胞质穿透机制的细菌的吞噬作用也会导致I类MHC分子呈递细菌抗原。此外，这种机制对放线菌酮和布雷菲德菌素A具有抗性，而这两种物质会阻断经典的I类加工途径。这些结果提示了一种针对外源性吞噬抗原的新型液泡I类加工途径。
