Studies of biological properties of the recombinants between human influenza and fowl plague viruses as related to genome composition.

Some biological properties of recombinants obtained by crossing of fowl plague and human influenza viruses were studied. The capacity of the recombinants to reproduce in chick embryo fibroblast cultures was in reverse correlation to the number of genes coding for P proteins derived from the human influenza virus. The genome composition was of importance for the expression of ts-phenotype of the recombinants in different systems. Substitution of at least one gene in the fowl plague virus genome by a corresponding human influenza virus gene resulted in the decrease of virulence for 1-day-old chickens. The presence of three P genes from human influenza virus genome in the genome of the recombinant proved to be insufficient for the capability of the recombinant to reproduce in organ cultures of human origin.