CD8A and infection: The low frequencies may be due to the relatively low contribution of NP-directed T-cell responses, in comparison to the surface glycoprotein, which is the other important structure antigen of HTNV and can induce much stronger CTL responses than NP, as indicated in the studies of other Hantaviruses [23], [32], especially the report on SNV infections, in which the frequency of epitope-specific CD8+ T cells has been reported to be as high as 44.2% [23].