FIG 5.
Recombinant pH1N1 mutant virus growth kinetics in MDCK cells. (A and B) Canine MDCK cells were infected (MOI of 0.001) in triplicates with the recombinant viruses encoding different variants of NS1 and PA proteins (NS1MUT/PAMUT, NS1MUT/PAWT, NS1WT/PAMUT, and NS1WT/PAWT) and incubated at 33°C (A) or 37°C (B). Virus titers in infected cell TCS were determined at the indicated hours postinfection by an immunofocus assay. ns, not significant. (C) MDCK cells were infected with the indicated pH1N1 viruses and incubated at 33°C (top) or 37°C (bottom) for 3 days. Plaque phenotypes were assessed by immunostaining with the anti-NP monoclonal antibody HB-65.