MDCK CELL CULTURES SUPPLEMENTED WITH HIGH CONCENTRATIONS OF TRYPSIN EXHIBIT REMARKABLE SUSCEPTIBILITY TO INFLUENZA C VIRUS

摘要

Multiplication of influenza C virus in MDCK cell cultures increased with increasing concentrations of trypsin up to 160 mu g/ml, whereas maximum growth of influenza A virus in the same culture was observed at a concentration of 10 mu g/ml. In the presence of 160 mu g of trypsin per ml MDCK cells showed the same or even higher susceptibility to various strains of influenza C virus compared with HMV-II cells, a human melanoma cell line that has been reported to have high susceptibility to the virus. Complete cleavage of the HE precursor protein of MDCK-grown influenza C virus into HE(1) and HE(2) subunits was achieved by trypsin at a concentration of 160 mu g/ml, whereas only partial cleavage was observed at 10 mu g/ml. The present results thus demonstrate that MDCK cell cultures supplemented with trypsin at a concentration of 160 mu g/ml become highly susceptible to influenza C virus.