Vallon-Eberhard Alexandra, Landsman Limor, Yogev Nir, Verrier Bernard, Jung Steffen
Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel.
J Immunol. 2006 Feb 15;176(4):2465-9. doi: 10.4049/jimmunol.176.4.2465.
The lamina propria that underlies and stabilizes the gut lining epithelium is densely populated with strategically located mononuclear phagocytes. Collectively, these lamina propria macrophages and dendritic cells (DC) are believed to be crucial for tissue homeostasis as well as the innate and adaptive host defense. Lamina propria DC were recently shown to gain direct access to the intestinal lumen by virtue of epithelium-penetrating dendrites. However, the role of these structures in pathogen uptake remains under debate. In this study, we report that entry of a noninvasive model pathogen (Aspergillus fumigatus conidia) into the murine small intestinal lamina propria persists in the absence of either transepithelial dendrites or lamina propria DC and macrophages. Our results suggest the existence of multiple pathogen entry pathways and point at the importance of villus M cells in the uptake of gut lumen Ags. Interestingly, transepithelial dendrites seem altogether absent from the small intestine of BALB/c mice suggesting that the function of lamina propria DC extensions resides in their potential selectivity for luminal Ags, rather than in general uptake or gut homeostasis.
位于肠道内衬上皮下方并使其稳定的固有层中密集分布着位置关键的单核吞噬细胞。总体而言，这些固有层巨噬细胞和树突状细胞（DC）被认为对组织稳态以及先天性和适应性宿主防御至关重要。最近研究表明，固有层DC凭借穿透上皮的树突直接进入肠腔。然而，这些结构在病原体摄取中的作用仍存在争议。在本研究中，我们报告了一种非侵袭性模型病原体（烟曲霉分生孢子）进入小鼠小肠固有层的过程，该过程在没有跨上皮树突或固有层DC及巨噬细胞的情况下仍会持续。我们的结果表明存在多种病原体进入途径，并指出绒毛M细胞在摄取肠腔抗原中的重要性。有趣的是，BALB/c小鼠的小肠中似乎完全没有跨上皮树突，这表明固有层DC延伸的功能在于其对腔内抗原的潜在选择性，而非一般的摄取或肠道稳态。
