The increased populations of regulatory T cells in peripheral blood of gastric
carcinoma reflect compromised host immunity. In this study, the murine model of
benzo[a]pyrene induced forestomach carcinoma was used to analyze the distribution
of regulatory T cells in different lymphoid tissues, including the regional lymph nodes,
the peripheral lymph nodes, spleen, and thymus. The proportions of regulatory T cells
in total CD4+ T cells is clearly more increased in regional lymph nodes than other
lymphoid tissues in benzo[a]pyrene-treated mice. These regulatory T cells expressed
the Foxp3 transcript and protein and were dramatically enhanced in regional lymph
nodes relative to peripheral lymph nodes. They were also enriched in CD62L- cell
subset and expressed both CCR1 and CCR5 chemokine receptors. These results
demonstrate that the accumulation of Treg cells in the regional lymph nodes mediated
local suppressive immunity during progression of forestomach tumours.
