Malaviya R, Twesten N J, Ross E A, Abraham S N, Pfeifer J D
Department of Pathology, Jewish Hospital of St. Louis, MO 63110, USA.
J Immunol. 1996 Feb 15;156(4):1490-6.
The pivotal role of mast cells in allergic reactions and inflammatory processes is well established and recent studies have suggested that mast cells may also have a role in specific immune responses. Because mast cells have been shown to phagocytose and kill enterobacteria, we wished to determine whether they could also process bacterial Ags for presentation to T cells. Using a model system in which a well-characterized T cell epitope is expressed within bacteria as a fusion protein, we demonstrate in this paper that mast cells are indeed capable of processing bacterial Ags for presentation through class I MHC molecules to T cell hybridomas after phagocytic uptake of live bacteria. Processing occurs from a number of Gram-negative enterobacteria including Salmonella typhimurium and Escherichia coli. Parallel assays show that processing of the model Ag from enterobacteria by mast cells is similar in efficiency to processing by peritoneal macrophages. Consistent with earlier observations demonstrating a function of the bacterial fimbrial protein FimH in promoting bacterial binding to mast cells, the magnitude of the Ag processing response of E. coli is influenced by bacterial expression of FimH. Taken together, these observations extend the range of cell types capable of the phagocytic pathway of Ag processing and suggest that mast cells may have a previously unrecognized role in the induction of specific immune responses to bacteria.
肥大细胞在过敏反应和炎症过程中的关键作用已得到充分证实，最近的研究表明肥大细胞在特异性免疫反应中可能也发挥作用。由于已证明肥大细胞可吞噬并杀死肠道细菌，我们希望确定它们是否还能处理细菌抗原以呈递给T细胞。在一个模型系统中，一个特征明确的T细胞表位在细菌内作为融合蛋白表达，我们在本文中证明，肥大细胞在吞噬活细菌后，确实能够处理细菌抗原，并通过I类主要组织相容性复合体（MHC）分子将其呈递给T细胞杂交瘤。多种革兰氏阴性肠道细菌包括鼠伤寒沙门氏菌和大肠杆菌都能发生这种处理过程。平行试验表明，肥大细胞处理来自肠道细菌的模型抗原的效率与腹腔巨噬细胞处理的效率相似。与早期观察结果一致，早期观察证明细菌菌毛蛋白FimH在促进细菌与肥大细胞结合中起作用，大肠杆菌的抗原处理反应程度受FimH细菌表达的影响。综上所述，这些观察结果扩展了能够进行抗原处理吞噬途径的细胞类型范围，并表明肥大细胞在诱导针对细菌的特异性免疫反应中可能具有以前未被认识的作用。
