[The role of antibody functional activity in the protection of people against influenza].

Indices of the functional activity of specific serum antibodies (IFAA) before and after outbreaks of influenza A (H3N2) and B were determined in 164 subjects of 18-20 years of age from the military communities observed in 1987-1988. The IFAA were calculated on the basis of kinetic HI tests followed by computer processing according to the program developed by the authors. The IFAA were found to indicate the protection of human subjects against influenza, reflecting the state of resistance to influenza more exactly than antibody titres. High initial IFAA correlated with lower severity of influenza infection. The IFAA to the same strain may differ significantly in individual subjects. In patients with influenza the time course of antibody titres did not coincide with dynamic changes in IFAA.