Houde Mathieu, Bertholet Sylvie, Gagnon Etienne, Brunet Sylvain, Goyette Guillaume, Laplante Annie, Princiotta Michael F, Thibault Pierre, Sacks David, Desjardins Michel
Département de pathologie et biologie cellulaire, Université de Montréal, C.P.6128, Succ centre-ville, Montréal, Québec, H3C 3J7, Canada.
Nature. 2003 Sep 25;425(6956):402-6. doi: 10.1038/nature01912.
The ability to process microbial antigens and present them at the surface of cells is an important aspect of our innate ability to clear infections. It is generally accepted that antigens in the cytoplasm are loaded in the endoplasmic reticulum and presented at the cell surface on major histocompatibility complex (MHC) class I molecules, whereas peptides present in endo/phagocytic compartments are presented on MHC class II molecules. Despite the apparent segregation of the class I and class II pathways, antigens from intracellular pathogens including mycobacteria, Escherichia coli, Salmonella typhimurium, Brucella abortus and Leishmania, have been shown to elicit an MHC class-I-dependent CD8+ T-cell response, a process referred to as cross-presentation. The cellular mechanisms allowing the cross-presentation pathway are poorly understood. Here we show that phagosomes display the elements and properties needed to be self-sufficient for the cross-presentation of exogenous antigens, a newly ascribed function linked to phagocytosis mediated by the endoplasmic reticulum.
处理微生物抗原并将其呈递到细胞表面的能力是我们清除感染的先天能力的一个重要方面。一般认为，细胞质中的抗原在内质网中加载，并在主要组织相容性复合体（MHC）I类分子上呈递到细胞表面，而存在于内吞/吞噬区室中的肽则在MHC II类分子上呈递。尽管I类和II类途径明显分开，但来自细胞内病原体（包括分枝杆菌、大肠杆菌、鼠伤寒沙门氏菌、流产布鲁氏菌和利什曼原虫）的抗原已被证明能引发MHC I类依赖性CD8 + T细胞反应，这一过程称为交叉呈递。允许交叉呈递途径的细胞机制尚不清楚。在这里，我们表明吞噬体展示了对外源抗原进行交叉呈递所需的元件和特性，这是一种与内质网介导的吞噬作用相关的新赋予的功能。
