[Production of influenza virus recombinations].

Described in this paper is the preparation of influenza virus recombination partners, H3N2 and H3N1, by poly-infection of primary embryonic fowl cells with influenza virus A/Greifswald/6/74 (H3N2) or with A/Greifswald/1/76 (H3N2) and A/PR/8/34 (H0N1). Purification was based on four consecutive plaque isolations. The productivity of all recombination partners isolated in the embryonated fowl egg was higher than that of parent strain, H3N2. A recombination partner of H0N2 was obtained from poly-infection of isolated chorio-allantois membranes (CAM) with inactivated influenza virus A/PR/8/34 (H0N1) and A/Greifswald/6/74 (H3N2), the whole process being exposed to the action of serum anti-H3N1. Purification was undertaken via plaque passages, as well. The recombination partners could be characterised by determination of haemagglutination titres in the embryonated fowl egg and by reference to plaque diameters.