The polysaccharide chitosan modulates the cellular and cytokine mesenteric lymph node milieu

PORPORATTO C, CANALI MM, RIERA CM, CORREA SG

Río de Janeiro

Congreso; XIII International Congress of Immunology and VIII Latin American Congress of Immunology (ALAI).; 2007

IUIS y ALAI

The mucosal immune system maintains a non responsive condition despite the close proximity of a vast amount of immunostimulatory bacteria and food antigens. During this natural phenomenon, called oral tolerance, the cellular and the cytokine components present in the mesenteric lymph nodes (MLN) play a central role. Chitosan (Ch) is a natural and abundant polysaccharide with mucosal immunostimulatory properties that make it a good candidate for the immunointervention of the mucosal immunity. Our purpose was to characterize the effects of oral administration of Ch to Wistar rats on the distribution and function of mesenteric dendritics cells (DC). Early after Ch feeding, we observed both, an increase in the percentage of MHC class II+ CD103+ CD4+dendritic cells (DC) and a greater IL-10+ CD103+ DC number in MLN in a dose dependent manner (flow cytometry, p<0.05). We evaluated if the increase in these anti-inflammatory DC present in Ch-fed rats could affect the proliferation capacity of MLN CD4+ T cells. As expected, we observed a significantly decrease in CD4+ T cells proliferation after Con A treatment (CFSE-flow cytometry) and a 10 to 30 percentage less IFNg levels in the supernatants of these cultures (ELISA; p<0.05) compared to control rats. These results suggest that the increase in the number of anti-inflammatory mucosal DC, the suppression of mesenteric CD4+ T cells proliferation and the diminished IFN-g production by these cells observed after Ch feeding could be important in the homeostasis preservation and oral tolerance induction in the intestinal mucosal.