Fig. 2

Infected bat cells produced significantly less progeny influenza viruses and viral M-gene RNA than correspondingly infected MDCK cells. Cells of all three bat species (TB1-Lu, E. helvum and C. perspic) and MDCK cells were infected with human or avian viruses at 0.5 MOI (based on focus forming assays) for 24 h. Supernatants were titrated on MDCK cells in 6 h focus forming assays to quantify progeny virus release. Infected bat cells of all three species produced significantly less viable virus than correspondingly infected MDCK cells (a-d). TB1-Lu cells released the least progeny virus among the three bat species. Furthermore, proportionally more progeny avian (H2N3 and H6N1) than human (USSR and pdm H1N1) viruses were produced from each species of bat cells. Results shown are the combined results of three independent experiments. Typically virus output from infected MDCK cells is in the region of 200 ffu/μl (a-d). Extracted total RNAs were quantified for viral M-gene expression normalised to 18 s rRNA (e and f). Cells of all three bat species produced significantly less viral M-gene RNA than MDCK cells with each virus. Each species of bat cells also generated more M-gene RNA from avian H2N3 virus than from USSR H1N1 virus infection. Results are representative of three experimental repeats