The British reference preparation for influenza virus haemagglutinin.
The two methods for measuring the haemagglutinin content of an influenza virus suspension are the haemagglutinating (HA) and chick cell agglutinating (CCA) techniques and both measure the same biological activity. With the establishment of an international reference preparation for influenza virus haemagglutinin (type A), however, it seems logical to express the haemagglutinin content of influenza vaccines in international units. Accordingly a collaborative study was arranged in order to obtain agreement on the number of units to be assigned to a British reference preparation for influenza haemagglutinin. It was agreed that the preparation contains 190 i.u. per ampoule and 1 i.u. is contained in 0.0622 mg. of the dried material.
D000818:Animals; D000941:Antigens; D002645:Chickens; D006386:Hemagglutination Tests / Q000592:standards*; D006389:Hemagglutinins, Viral / Q000592:standards; D007391:International Cooperation; D009975:Orthomyxoviridae / Q000276:immunology*; D006113:United Kingdom; D014765:Viral Vaccines / Q000592:standards
D000941:Antigens; D006389:Hemagglutinins, Viral; D014765:Viral Vaccines