Abstract:

【Objective】 The immune response of immunized ducklings induced by goose parvovirus VP3 gene vaccine（pcDNA-GPV-VP3）and attenuated vaccine was compared for providing experimental data for explaination of immune mechanisms and immune duration of pcDNA-GPV-VP3.【Method】 The 30-day-old Sichuan White Geese were immunized with pcDNA-GPV-VP3 gene vaccine and attenuated vaccine of GPV. The antigens of GPV were detected by immunohistochemistry method. To compare the immune response ability of goose induced by gene vaccine and attenuated vaccine, the cell immunity effect and serum antibody titer were detected by lymphocyte proliferation assay and indirect ELISA, respectively. 【Result】 The GPV antigen was detected in the heart, liver, spleen, lung, kidney, bursa of Fabricius, thymus, Harder's glands, duodenum, jejunum, ileum, rectum, appendix, pancreas, cerebrum and injection muscle of goose in attenuated vaccine group. In gene vaccine group, the GPV antigen was detected in the heart, duodenum, jejunum, ileum, rectum, appendix, pancreas, cerebrum and injection muscle of goose. The action of T lymphocyte to ConA was enhanced in peripheral blood of immunized goose with attenuated vaccine from 14th day. It reached the highest at 35th day. The OD value of T lymphocyte descended at first in the gene vaccine group. It rose at 14th day and reached the highest at 35th day. The value in 21-63 d was higher than that of the control group and attenunated vaccine group, the difference was extremely significant (P＜0.01). The serum antibody titer of goose immunized with attenuated vaccine was higher than that of PBS control group from 3rd day. It reached the highest at 28th day. The serum antibody titer of goose immunized with gene vaccine was higher than that of PBS control group from 14th day. It reached the highest at 28th day. The value in 21-217 d was higher than that of the control group, the difference was significant (P＜0.05) or extremely significant (P＜0.01). The serum antibody titer of goose immunized with gene vaccine and attenuated vaccine had no obvious difference at any time except that in 28th day, and the difference was extremely significant (P＜0.01). 【Conclusion】The pcDNA-GPV-VP3 gene vaccine could express in the immunized muscle, heart and intestines of goose and induced favorable cell immunity and humoral immunity. The immune response ability induced by gene vaccine has more advantages than by attenuated vaccine. It is helpful to explain the immunologic mechanism and clinical application of pcDNA-GPV-VP3.

Key words: gosling plague virus, gene vaccine, attenuated vaccine, geese, cell immunity, antibody