Immunoperoxidase detection of baculovirus antigens in insect cells

The sequence of events in the infection of TN-368-10 and TN-368-13 cells by Autographa californica nuclear polyhedrosis virus (AcMNPV) was investigated by using the indirect immunoperoxidase technique. Antisera raised against enveloped nucleocapsids detected homologous antigens at 6 to 8 h post infection which was about 2 h before the appearance of both intracellular and extracellular infectious virus. Similar tests using polyhedrin antiserum showed that polyhedrin is first synthesized at 12 h post infection, 2 to 4 h after the appearance of infectious nonoccluded virus. The immunoperoxidase technique was also applied to four other invertebrate cell lines after inoculation with AcMNPV. The most significant result was that 90% of AcMNPV-inoculated Bombyx mori 5 cells produced enveloped nucleocapsid antigens and infectious virus but only 1% or less of the cells produced polyhedrin. This disparity emphasizes the need for assays for NPV infection that are independent of polyhedron production.