Fig. 3.

Hypoxia stimulates extracellular transmission of LCMV. Filtered medium from HeLa-MX cells that were cultured under normoxia or hypoxia for 48 h was used for infection of noninfected HeLa cells. The cells were then cultivated under normoxic conditions and subsequently passaged. (A) The presence of the LCMV genome in the medium from HeLa-MX cells cultured under normoxia (NO) or hypoxia (HY) was detected by the RT-PCR method. (B) The spread of infection in HeLa cells infected with the indicated medium was monitored by RT-PCR analysis in the first 5 passages and then in the 10th passage. (C) The progress of infection was also monitored by immunofluorescence detection of viral nucleoprotein in recipient cells. Magnification, ×20. The experiment was repeated three times, each time showing similar results. P, passage.