Isolation and Egg-Yolk Antibody Preparation of Micropterus salmonides Rhabdovirus

Abstract:

The largemouth bass Micropterus salmoides has been widely cultured in China due to its considerable economic value. Recently, the species suffered from serious M. salmoides rhabdovirus (MSRV) disease during the juvenile phase, particularly in aquaculture conditions. In this study, a strain of M. salmoides rhabdovirus isolated from dying juvenile fish was cultured in a grass carp ovary (CO) cell line. To take advantage of passive immunity, we explored anti-MSRV immunoglobin Y (IgY) by discontinuously immunization on laying hens with a formalin-killed vaccine of MSRV. The antibody was purified by saturated ammonium sulfate, and displayed virus resistance with an ELISA antibody titer of 1∶256 detected. The bioactivity of anti-MSRV IgY was tested simultaneously after being added to a CO cell line incubated with MSRV. This antibody showed antiviral activity, with 38.29% of neutralizing effectiveness detected at a dilution of 1∶64. The RNA copies of MSRV in the test group were clearly fewer in number compared with those of members of a control group. By the florescent real-time quantitative PCR, the intracellular lectin experienced significantly up-regulated pick-up to nearly 10-fold at 72 h compared with the control group. In conclusion, we successfully isolated a strain of MRSV and cultured it in a CO cell line. Anti-MSRV IgY prepared with vaccinations of inactive virus displayed antiviral activity in this study, laying a foundation for the application of yolk antibodies as an immune preparation.