IMMUNOFLUORESCENT STUDY ON THE PATHOGENESIS OF ORAL INFECTION OF POLIOVIRUS IN MONKEY

Abstract

Cynomolgus monkeys were fed with a virulent strain of type 1 poliovirus (Mahoney), and the site of initial multiplication of the virus in the alimentary tract was investigated immunofluorescently. The virus antigen appeared as short as 24 hr after the feeding in both the squamous epithelial cells of the oropharynx and the macrophages of lymphatic structure of the tonsils. The virus antigen was also detectable at the early stage of infection in the reticulo-endothelial cells of the lamina propria of the intestines. Multiplication of poliovirus in the endothelial cells was substantiated by electron-microscopic demonstration of a characteristic crystalline inclusion consisting of poliovirus-like particles in the cytoplasm of the cells. No convincing evidence supporting multiplication of the virus in the mucosal epithelium of the intestines was obtained. Macrophages with intracytoplasmic fluorescence appeared abundantly after the onset of viremia in the lymph nodes, the spleen and the liver. Poliovirus antigen appeared after the onset of paralysis in the central nervous system, particularly in high concentrations in the motor nerve cells of the spinal cord. Poliovirus antigen was also detectable in inflammatory cells, principally the neutrophilic leucocytes, of various tissues at the late stage of infection.