Rabbit anti-caveolin 1 polyclonal antibody (pAb), mouse anti-caveolin 1 monoclonal antibody (mAb) mouse anti-EGFP mAb (JL-8) (all BD Transduction Laboratories) mouse anti-Influenza A virus M2 monoclonal antibody (14C2, ABR) were used according to the suggestions of the supplier. 