Effect of different inactivation methods on different stages of the viral replication cycle. Macrophages were incubated with inactivated LV or untreated LV for 1 h at 4 °C and 1, 5 or 10 h at 37 °C. After fixing and immunofluorescence staining of the cells, attachment (1 hpi at 4 °C), internalization (1 hpi at 37 °C), disassembly (5 hpi at 37 °C) and replication (10 hpi at 37 °C) was analyzed by confocal microscopy.