Biochemical characterization and time-course analysis of Lymantria dispar nuclear polyhedrosis virus with monoclonal antibodies

Hybridoma cell lines secreting monoclonal antibodies (MAbs) specific to a 31 000 molecular weight viral protein or a 31 000 molecular weight polyhedrin protein of Lymantria dispar nuclear polyhedrosis virus (LdNPV) were developed. The two polypeptides were shown to be different by comparing their amino acid compositions. Immuno-electron microscopy was used to verify specific binding of the MAbs to their respective targets. Specific MAbs were used to develop an ELISA procedure to monitor the development of LdNPV virus and polyhedrin in vivo. Results indicated that in hemolymph of larvae fed 106 polyhedral inclusion bodies, the concentration of virus began to increase 16 h after inoculation and continued to increase for the next 5 days. By 36 h, the concentration of polyhedrin increased and was maintained at a high level in the later stages of infection. One-third of this group of infected larvae survived the infection. In these individuals, the concentrations of virus and polyhedrin declined to a low level 5 days after infection. This suggests the presence of a host mechanism for clearing the virus from the hemolymph. Key words: infection mechanism, monoclonal antibody, in vitro immunization, Lymantria dispar nuclear polyhedrosis virus, ELISA.