Aquaculture Department, Southeast Asian Fisheries Development Center
Abstract
Monodon baculovirus (MBV) and hepatopancreatic parvovirus (HPV) are two of the viral pathogens, which infect penaeid shrimps in the Philippines. Polyclonal antibodies (PAbs) to MBV and HPV were raised by immunization of rabbits with the purified virions. The antisera produced were assessed using immunofluorescence antibody test (IFAT), indirect enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC). IFAT showed intense fluorescent reactions in impression smears and paraffin-embedded sections of MBV-infected P. monodon postlarvae (PLs) but not in smears and/or sections infected with HPV or WSSV. Similarly, IHC tests showed positive coloration in MBV-infected cells but not in sections with either HPV or WSSV. Indirect ELISA test revealed that the PAbs could detect 4 ng (rabbit 1) and 100 ng (rabbit 2) of purified MBV. However, testing of crude shrimp homogenates by indirect ELISA indicated high level cross-reactions (gills of WSSV-infected adult P. monodon, head portions of HPV- and MBV-infected PLs and non-infected PLs). Screening of anti-HPV serum likewise showed intense immunofluorescence and positive red brownish coloration in HPV-infected sections. However, there were also strong cross-reactions observed in sections of hepatopancreas with MBV infection. Overall, the MBV PAbs developed have potential application in the detection of the virus. Further purification of the PAbs is required to minimize background and/or cross-reactions
