PATHOGENESIS AND IMMUNOGENICITY OF BOVINE ADENOVIRUS TYPE-3 IN COTTONRATS (SIGMODON HISPIDUS)

Intranasal inoculation of cotton rats (Sigmodon hispidus) with 10(8) P FU of bovine adenovirus type 3 (BAd3) resulted in limited virus replic ation in the lung and trachea. Histopathological changes in the lungs were characterized by necrosis and hyperplasia of bronchiolar epitheli um, eosinophilic intranuclear inclusions, pneumocyte type II hyperplas ia in the alveoli, and mild peribronchiolar and perivascular lymphocyt ic infiltration. Immunohistochemically, viral antigens were observed m ore frequently in bronchiolar epithelial cells than in alveolar cells in cotton rat lung sections stained using a rabbit anti-BAd3 serum. Br onchiolar epithelial changes, intranuclear inclusion bodies, type II p neumocyte proliferation, peribronchiolar infiltration, and immunohisto logical staining were maximum at Day 3 or Day 4 postinoculation, where as perivascular infiltration was first observed at Day 8 postinoculati on. In addition to the histological study of the pathogenesis of BAd3 infection, we monitored the BAd3-specific immune response in cotton ra ts. Anti-BAd3 IgG and virus neutralizing antibodies were detected in s era, whereas anti-BAd3 IgA antibodies were found in the sera, lung, an d nasal washes. Our results suggest that the cotton rat can serve as a useful small-animal model for investigating the pathogenesis of BAd3 infection, as well as immune responses to BAd3 recombinant virus vacci nes. (C) 1995 Academic Press, Inc.