?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 determine how HPAI H5N1 viruses stimulate the activation of γδ T cells. HA is the most abundant antigen on the surface of influenza viruses. Therefore, we used recombinant hemagglutinin (rHA) proteins to investigate the interplay between the HPAI H5N1 virus and γδ T cells. Two forms of rHA proteins, namely HAF and HA-his, were constructed as previously reported (Figure 3A ) (23) . The expression of the rH5HA proteins was confirmed by Coomassie blue staining ( Figure 3B ) and by Western blotting using antibodies against the His tag ( Figure 3C ) and HA (Figure 3D) . Gel filtration chromatography was further conducted to analyze the oligomerization of rHA proteins. The majority of the HAF protein appeared as an HA trimer, while the HA-his protein appeared as an HA monomer; a few oligomeric proteins were present in both groups (Figure 3E ). Both the HAF and HA-his proteins showed hemagglutination activity (Figure 3F) , indicating their ability to bind sialo-glycoconjugates on the erythrocytes. However, higher binding ability was observed for HAF proteins than for HA-his proteins ( Figure 3F ).