Preparation of rubella virus haemagglutinating antigen by polyethlene glycol precipitation

Polyethylene glycol (PEG) was used for precipitation of rubella virus haemagglutinating (HA) antigen from the fluid phase of infected Vero cell cultures, maintained with or without calf serum. In both cases potent antigen preparation were obtained. When the antigen was precipitated from serum-containing medium, higher titres were obtained, provided that substrate or final product were treated with Tween 80 and ether. HA antigen obtained by PET precipitation was entirely valuable in the haemagglutination-inhibition test, as compared with antigens prepared by other methods.