Cultivation of Rubella Virus in Avian Tissue Cultures and Embryonated Eggs

Summary The cultivation of rubella virus in avian tissue culture systems, and particularly in RIF-free chick embryo tissue culture, is of importance in the development of safe attenuated rubella virus vaccines for parenteral administration. Nine virulent or attenuated rubella virus strains were propagated for at least 3 passages in RIF-free chick embryo tissue culture or duck embryo tissue culture. Several strains showed growth in duck and chick tissue through the 5th to 7th passages. Highest titers were usually obtained when passages were made at intervals of 7 or more days. Virus titers varied from 1.2 to 4.5 TCIND50 log 10/ml in duck tissue culture at the 5th to 7th passages, and 1.0 to 1.5 TCIND50 log10/ml in chick tissue culture at the 5th passage level. Virus growth was demonstrated in early passages in embryonated duck eggs but no detectable growth was obtained in chick eggs. The propagation of rubella virus in RIF-free chick embryo tissue culture warrants further efforts at the development of an attenuated rubella vaccine in this tissue culture system.