Martinoli Chiara, Chiavelli Andrea, Rescigno Maria
Department of Experimental Oncology, European Institute of Oncology, I-20124 Milan, Italy.
Immunity. 2007 Dec;27(6):975-84. doi: 10.1016/j.immuni.2007.10.011.
Secretory immunoglobulin A (SIgA) represents a first line of defense against mucosal pathogens by limiting their entrance. By using different strains of Salmonella typhimurium that target the two mechanisms of bacterial entry (microfold cell [M cell]- or dendritic cell-mediated), we demonstrated here that the distribution of bacteria after oral infection directed the type of induced immune response. M cell-penetrating invasive, but not noninvasive, S. typhimurium was found in large numbers in Peyer's patches (PPs), leading to the activation of immune cells and the release of fecal IgA. In contrast, both strains of bacteria were equally capable of reaching the mesenteric lymph node and the spleen and inducing IgG responses. These data suggest that PPs are absolutely required for the initiation of an IgA response to Salmonella, whereas they are dispensable for a systemic response. This compartmentalization could allow the fast generation of both mucosal and systemic acquired immunity to pathogens.
分泌型免疫球蛋白A（SIgA）通过限制病原体进入，构成抵御黏膜病原体的第一道防线。利用靶向细菌进入的两种机制（微褶细胞[M细胞]介导或树突状细胞介导）的不同鼠伤寒沙门氏菌菌株，我们在此证明口服感染后细菌的分布决定了诱导免疫反应的类型。发现穿透M细胞的侵袭性鼠伤寒沙门氏菌（而非非侵袭性菌株）大量存在于派尔集合淋巴结（PPs）中，导致免疫细胞活化和粪便IgA释放。相比之下，两种菌株都同样能够到达肠系膜淋巴结和脾脏并诱导IgG反应。这些数据表明，PPs对于启动针对沙门氏菌的IgA反应是绝对必需的，而对于全身反应则并非必需。这种分隔能够使机体快速产生针对病原体的黏膜和全身获得性免疫。
