Studies on the immune response and pathogenesis of Sendai virus infection of mice. I. The fate of viral antigens.

The distribution of viral antigens was determined in lungs, spleen and bronchial lymph nodes of a non-lethal primary Sendai virus infection of mice. Immunofluorescent staining showed that virus was initially confined to the bronchial mucosal columnar cells. Most antigen was present in this location between the 3rd and 5th days a finding which correlated well with infectivity assays. From the 3rd day desquamated mucosal cells in the bronchial lumen showed relatively weak staining for viral antigens. Alveolar macrophages were shown to contain viral antigens only after mucosal shedding had occurred. Viral antigens were found in bronchial lymph nodes between the 3rd to 9th days, and in the spleen from the 3rd day to 49th day after infection. Virus could not be grown from the spleen at any time. It was shown that the intraluminal cellular debris which appeared to contain little virus was coated with immunoglobulin. More viral antigen could be detected in this location after acid and alkali elution and after prolonged incubation with a potent heterologous anti-viral antiserum. It was concluded that early mouse antibody was fixed to viral antigens in the lung 3 days after infection and 5 days before it could be detected in serum or bronchial secretions. The significance of these findings was discussed.