Abstract: | Two collective bodies (319 persons in all) were under observation from October, 1974 to March, 1975 for the purpose of studying the problem on the participation of antibodies of the respiratory tract secretion in the protection from influenza virus, type A, infection. During the influenza epidemic outbreak there was revealed a reverse relationship between the antibody concentration in the nasal cavity secretion and the incidence of the disease, and also an interaction between the antibodies of the secretions and the serum in the influenza protection. |