FIGURE 1.

Puumala virus (PUUV) immune peroxidase (IPOX) staining and viral copy numbers after infection with a multiplicity of infection (MOI) of 0.5 and 3. Mock infected cells (A,B) showed no red peroxidase staining for PUUV nucleoprotein after 24 (A) and 48 (B) hours. Twenty-four hours after infection with MOI 0.5 (C) a small number of cells stained positive, which, increased at 48 h (D). Infection with MOI 3 resulted in more infected cells after 24 h (E), which increased slightly at 48 h post infection (F). Analysis of viral replication showed a more than 2-log increase of viral copy numbers in both supernatant (G) and cell lysates (H), suggesting active viral replication. Bars represent SE of the mean. BPL inactivation of the virus lead to no increase in viral copy numbers in the supernatant and a negative IPOX staining (data not shown). Furthermore infection was confirmed by western blot for the presence of the PUUV nucleoprotein in the cell lysate and Von Willebrand Factor (VWF) to confirm the character of the endothelial cells (I). The first four lanes show control wells with only one band present at the upper side of the blot (VWF). The last for lanes show the presence of both VWF and the PUUV nucleoprotein (∼55 kDa 10ug/lane). Data are representative of three independent experiments.