FIG. 1.

Expression of HSP70 in MDCK cells infected with influenza virus at 41°C. (A) MDCK cells were infected with influenza virus and cultured at 37 or 41°C for the indicated times. The cells were lysed, and immunoblotting was performed with anti-HSP70 monoclonal antibody. The expression of HSP70 increased after 2-h of incubation at 41°C, but not at 37°C. (B) Infected MDCK cells were cultured at 37°C (a) or 41°C (b) for 6 h and stained immunofluorescently with anti-HSP70 antibody. HSP70 was observed only at 41°C and was localized specifically in the nuclei and nucleolus (arrowheads). Bar, 25 μm.