[VARIABILITY OF A VIRULENT STRAIN OF NEWCASTLE DISEASE VIRUS UNDER THE INFLUENCE OF HOMOLOGOUS IMMUNE SERA].
D002642:Chick Embryo; D007106:Immune Sera; D009522:Newcastle disease virus; D012106:Research; D046509:Tissue Culture Techniques
D007106:Immune Sera
CHICK EMBRYO; EXPERIMENTAL LAB STUDY; IMMUNE SERUMS; NEWCASTLE DISEASE VIRUS; TISSUE CULTURE