Studies on West Nile virus infection by means of fluorescent antibodies

Summary By means of infectivity titration of tissues and fluorescein-labeled antibody staining, the pathogenesis of West Nile virus in suckling mice was studied. When mice were inoculated intracerebrally, antigens were first detected in the central nervous system and in mesenchymal tissue. When mice were inoculated intraperitoneally, antigens were first detected in mesenchymal tissue and the plexus of Auerbach in the digestive tract. Additional antigens were soon found in the entire nervous system, the blood vessels, the smooth and skeletal muscle and other connective tissues. Involvement of the major organs and lymph nodes was minimal until the last 2 days of infection. The rise of tissue infectivity titers generally paralleled the observed spread of viral antigens. Nervous tissue and mesenchymal tissue appeared to show equal susceptibility to primary viral invasion and growth. The possibility that the blood vessel wall is one of the primary sites of multiplication for WN virus is suggested.Aided in part by a grant from the National Foundation and by Research Grant E 2514, U. 8. Public Health Service, Department of Health, Education and Welfare.