Yersinia enterocolitica target Peyer`s patch dendritic cell subpopulations to evade the immune response

ELIÇABE, JAVIER; DRECHTER, DOREEN; AUTENRIETH, STELLA; DI GENARO,SILVIA; AUTENRIETH, INGO

Buenos Aires

Congreso; First French - Argentine Immunology Congress.; 2010

Sociedad Argentina de Inmunologia y Sociedad Francesa de Inmunologia

The gut-associated lymphoid tissue (GALT) comprise the Peyers’s patches (PP) and mesenteric lymph nodes (MLN). Dendritic cells (DCs) are thought to be critical in the decision of whether to mount tolerant or protective immune responses. In PP and MLN, DCs consists of CD11c+CD11b+CD8a-, CD11c+CD11b-CD8a+, and CD11c+CD11b-CD8a- subsets (double negative; DN). Yersinia enterocolitica (Ye) is a Gram-negative pathogen that causes gastrointestinal diseases. Ye colonize the PP and may disseminate to the MLN, and subsequently, to spleen, liver, and lung. The interaction between Ye and mucosal DCs have not been previously investigated. The purpose of the present work was investigate the interaction and the role of mucosal DC subpopulations in enteric Ye infection. C57BL/6 mice (female 6 weeks-old) were orally infected with 5 x 108 Ye O:8 pYV+. Phosphate saline buffer (PBS) was orally administrated to a group of mice and used as control mice. After 3 or 5 days, animals were killed, PP were obtained and DCs were isolated. The phenotype of the isolated DCs were analysed by flow cytometry. Ours results indicate that Ye invades PP since colony forming units (CFU) were detected from this organ at days 3 and 5 after infection. A population with low CD11c  expression was observed in infected mice, suggesting monocyte migration to PP after Ye infection. On other hand, we observed a significant decrease of CD8+CD11b- and DN cells in infected mice compared with PBS control mice (p<0.01). In contrast, CD8-CD11b+ DCs increased in Ye infected mice compared with control mice (p<0,002). In conclusions, ours results suggested that Ye affect DC subpopulations of PP after oral infection, inducing decrease of CD8+CD11b- and DN DCs and increase of CD8-CD11b+ DCs. Since CD8+CD11b- and DN DCs induces Th1 response which plays a critical role in the immune response to Ye, this result suggests that Ye could target theses DC subpopulations to evade the immune response.