?d T Cells Provide Protective Function in Highly Pathogenic Avian H5N1 Influenza A Virus Infection

Dong, Peng; Ju, Xiangwu; Yan, Yiwu; Zhang, Siya; Cai, Menghua; Wang, Huaishan; Chen, Hui; Hu, Yu; Cui, Lianxian; Zhang, Jianmin; He, Wei

Next, we sought to explore the mechanism underlying γδ T cellmediated protection against H5N1 viral infection. The interplay between HPAI H5N1 virus and human γδ T cells has not been reported. To determine whether HPAI H5N1 virus could directly induce human γδ T cell activation in vitro, human γδ T cells were isolated from healthy donors and expanded before infection (Figures 2A,B) . In addition, the expression of CD69 was significantly upregulated following HPAI H5N1 virus infection (Figures 2C,D) . Furthermore, the secretion levels of the cytokines GM-CSF, IFN-γ, TNF-α, IL-4, and IL-5 in γδ T cells were markedly increased after HPAI H5N1 infection ( Figure 2E) . Nevertheless, the viral M1 protein could not be detected after HPAI H5N1 infection ( Figure 2F) . Taken together, these results indicate that γδ T cells could be activated by HPAI H5N1 virus but are resistant to H5N1 infection.