Growth characteristics of influenza virus type C in avian hosts

Abstract
Influenza virus type C could be propagated to high yield in primary chick embryo kidney cell culture (PCEK) provided that trypsin (2 µg/ml) was used as a medium supplement. The virus could also be titrated by plaque assay using PCEK host cells and influenza C virus that had been plaque-purified in PCEK cells could then be serially passaged to high titer using the allantoic route of 10–11-day-old embryonated eggs.