Protective role of follicular CXCR5(+)CD8(+) T cells against dengue virus 2 infection

Follicular CXCR5(+)CD8(+) T cells have antiviral effects in chronic virus infection, but the roles of these cells during dengue virus 2 (DENV2) infection remain poorly understood. OBJECTIVE: This study was conducted to analyzed in detail the dynamic changes and functional properties of circulating follicular CXCR5(+)CD8(+) T cells to explore their effects on DENV2 infection. METHODS: Circulating follicular CXCR5(+)CD8(+) T cells and cytokines were analyzed by flow cytometry in DENV2 patients at difference days after DENV2 infection. CD8(+) T cells were isolated and purified from DENV2 patients, then were stimulated with NS1 peptides and TCR stimulant. After cultivation, multiple parameters were tested. RESULTS: (1) CXCR5(+)CD8(+) T cells emerged after DENV2 infection, with high PD-1 expression, and were correlated with the reduction in DENV2 RNA viral loads. (2) PD-1(+)CXCR5(+)CD8(+) T cells were negatively associated with disease progression. (3) Serum IFN-γ, IL-6 and IL-10 levels were increased late in the course of DENV2 infection. (4) CXCR5(+)CD8(+) T cells from DENV2 patients exhibited increased cytotoxicity and IFN-γ and IL-10 secretion. CONCLUSION: CXCR5(+)CD8(+) T cells could play a protective role in dengue pathogenesis and may be a novel strategy for controlling DENV2 infection and vaccine development.