TLR7 Modulated T Cell Response in the Mesenteric Lymph Node of -Infected C57BL/6 Mice.

Toll-like receptors (TLRs) play an important role in regulating immune responses during pathogen infection. However, roles of TLRs on T cells reside in the mesenteric lymph node (MLN) were not be fully elucidated in the course of infection. In this study, T lymphocytes from the mesenteric lymph node (MLN) of -infected mice were isolated and the expression and roles of TLR2, TLR3, TLR4, and TLR7 on both CD4 and CD8 T cells were compared. We found that the expression of TLR7 was increased in the MLN cells of -infected mice, particularly in CD4 and CD8 T cells ( < 0.05). R848, a TLR7 agonist, could enhance the production of IFN- from MLN T cells of infected mice ( < 0.05), especially in CD8 T cells ( < 0.01). In TLR7 gene knockedout (KO) mice, the infection caused a significant decrease ( < 0.05) of the expression of CD25 and CD69, as well as the production of IFN- and IL-4 inducted by PMA plus ionomycin on both CD4 and CD8 T cells. Furthermore, the decreased level of IFN- and IL-4 in the supernatants of SEA- or SWA-stimulated mesenteric lymphocytes was detected ( < 0.05). Our results indicated that infection could induce the TLR7 expression on T cells in the MLN of C57BL/6 mice, and TLR7 mediates T cell response in the early phase of infection.