Antigenic and biochemical analysis of influenza "A" H3N2 viruses isolated from pigs

Four influenza A-H3N2 viruses isolated in pigs from different herds in Central Italy in the period 1981/82 have been antigenically and biochemically analysed. Three of them A/Sw/Italy/2/81, A/Sw/Italy/7/81, A/Sw/Italy/8/82 were found to be serologically related to A/Bangkok/1/79 (H3N2). These three viruses were shown to have an identical electrophoretic pattern, as regards virus induced polypeptides and were clearly distinguishable from the virus A/Sw/Italy/6/81 which was antigenically related to A/England/42/72 (H3N2) and A/Sw/Taiwan/7310/70 as shown by specific monoclonal and polyclonal antisera. The observed biochemical variations underline the importance of the changes occurring by genetic reassortments or mutations in human influenza viruses, during their maintenance in pigs.