Abstract
Host cell nuclear involvement in an arenavirus infection was examined by immunofluorescence. Both polyclonal antisera and monoclonal antibodies specific for the major nucleocapsid (N) polypeptide revealed virus-specific nuclear inclusions in Pichinde virus-infected Vero cells. Immunoprecipitation of infected cell extracts with the anti-N monoclonal antibodies and subsequent analysis by SDS-PAGE, identified two N-related proteins with mol. wt. of 36,000 (p36) and 28,000 (p28) in addition to the N polypeptide. Only those monoclonal antibodies which precipitated p28 as well as N and p36 were found to produce nuclear as well as cytoplasmic fluorescence. These findings suggest that either the p28 protein itself or a conformational variant of N was the nuclear antigen detected.