Serum neutralization of nucleopolyhedrosis viruses (Baculovirus subgroup A) pathogenic for Orgyia pseudotsugata

The preparation of antisera to intracellular nonoccluded virions and an in vivo neutralization test procedure (constant serum and virus in dilutions) are described. Results of homologous neutralization tests showed that rabbit antisera to two multicapsid viruses pathogenic for Orgyia pseudotsugata had higher neutralization indices than antiserum to a unicapsid Baculovrus from O. pseudotsugata. Based on reciprocal tests, the three viruses are antigenically distinguishable. Blood serum of rats which had been exposed by inhalation to 25 projected acre doses of a technical-grade Baculovirus preparation demonstrated no viral neutralizing activity. Since the neutralization test used in this study does not require availability of susceptible cell lines and is sensitive and accurate, it could find application in quality control programs and in field monitoring of Baculovirus strains.