Fig.2. Trypsin dependence of rhMPV-F and rhMPV.
LLC-MK 2 cells were infected by rhMPV-F or rhMPV and incubated with DMEM with or without 0.2μg/mL of trypsin-TPCK. Indirect immunostaining assay was performed at day 6 post-infection. After removal of cell culture medium, the cells were fixed in acetone: methanol (at the ratio of 3:2) and permeablized in PBS containing 0.4% Triton X-100. The cells were then probed with anti-hMPV N monoclonal antibody, followed by incubation with HRP-conjugated rabbit anti-mouse antibody. After incubation with AEC substrate chromogen, positive cells were visualized under light microscope.