PRNP and infection: No viral proteins weredetectable in N2aC24 cells at 4 dpi with 0.01 MOI of IAV/WSN after treatment with theanti-sera at the time of infection (Fig. 4a),indicating that the anti-sera successfully blocked IAV/WSN infection in N2aC24 cells.PK-resistant PrP fragments were also undetectable in the cells after 5 passages(Fig. 4b).