ATTENUATED COLD-ADAPTED STRAIN OF INFLUENZA VIRUS B USSR(69)E FOR PREPARING THE LIVE INTRANASAL ANTIINFLUENZA VACCINE

摘要

FIELD: medicinal virology. SUBSTANCE: vaccine strain B/USSR/60/E is obtained by 60-fold passage in developing chicken embryos at 25 C followed by additional 7-fold selective cloning the intermediate virus B/USSR/60/69 on chicken kidney tissue culture at 25 C. As a result, clone B/USSR/60/69/E has lost the capability to multiplicate in mouse respiratory tract lower regions. Strain has cold-adaptivity (ca MARKER) and temperature-sensitivity (t₃-MARKER). Strain has the following properties: hemagglutinating activity is 1:256; infectious activity is 7.5-8.5 lg EID 50/0.2 ml (infectious embryonic doses), and genetic stability after 5 passages in chicken embryos at optimal temperature. EFFECT: strain indicated above, enhanced quality and properties.