Mesenteric dendritic cells from germ-free mice cause less T-cell stimulation but still induce ?4?7 integrin

Abstract

Intestinal dendritic cells (DCs) have properties that distinguish them from DCs in other tissues. The intestinal microbiota influences the generation of the gut immune system but it is not known whether bacteria influence tissue-specific properties of intestinal DCs. In this study intestinal and non-intestinal DCs from germ-free (GF) and conventional (CONV) mice were compared. Mesenteric lymph node (MLN) DCs from GF mice were less stimulatory for T cells than their counterparts from CONV mice. Responses stimulated by Peyer’s patch (PP) DCs and peripheral lymph node (PLN) DCs were similar in GF and CONV mice. DCs from GF mice were competent for the generation of cytokine-producing effector T cells with interferon (IFN)-g production dominant. Gut (MLN and PP) DCs had tissue-specific properties that distinguished them from PLN DCs: lower CD40 expression, the presence of a major CD11blo DC subset and the ability to generate large numbers of T cells expressing the gut-homing integrin α 4β7. These differential properties of gut and PLN DCs were observed in both GF and CONV mice. These data suggest that the microbiota enhance the stimulatory capacity of MLN DCs but are not required for the generation of a number of distinctive properties of gut DCs. Key words: dendritic cells, bacteria, germ-free animals, intestinal microbiota