[Reactivity of the lymphoid-macrophage system in relation to the toxic properties of influenza virus].

: Influenza A2/Bethesda/10/63 virus, highly virulent for mice, replicated actively in the lungs, had comparatively low immunogenicity and a toxic effect manifested by the development of circulation disorders, hemorrhages in regional lymph nodes as well as damages of lymphoid and macrophage elements. Mouse avirulent A2/21/65 virus showing the same degree of reproduction, exerted no toxic effect in the respiratory organs, caused no considerable destructive changes in the lymphoid tissue and had comparatively greater immunogenicity. Comparatively low antibody titers after infection of mice with A2/Bethesda/10/63 virus may probably be due to the toxic effect of the virus on the lymphoidmacrophage system.