Studies On The Cellular And Humoral Immunities In Goslings Immunized With VP3 Gene Vaccine Of Goose Parvovirus

In this study, 28-day-old health goslings were immunized with pcDNA-GPV-VP3 DNA. T lymphocyte proliferation test(MTT) and indirect ELISA methods were employed respectively to detect cellular and humoral immune responses of goslings immuned with pcDNA-GPV-VP3 DNA vaccine.28-day-old health goslings were immunized by gene gun bombardment with three dosages(1μg,3μg and 6μg )of pcDNA-GPV-VP3 DNA vaccine and with,three dosages(50μg ,100μg and 200μg )by intramuscular injection.Goslings were also immunized by intramuscular administration with empty plasmid, PBS and the GPV attenuated vaccine as control. Blood samples were collected at 3d, 7d, 14d, 21d, 28d, 35d, 49d, 63d, 77d and 105d after injection for cellular immunity studies by T-lymphocyte proliferation test (MTT).And anticoagulation blood were collected at 3d, 7d, 14d, 21d, 28d, 35d, 49d, 63d, 77d,105d, 133d,161d,189d and 217d for humoral immunity studies by indirect ELISA.The results showed: The OD values of T-lymphocyte cell started to be decreased slightly from 3 to 14d, then gradually reached peak value at 35d.The OD values of intramuscular injection and gene gun bombardment group were significant higher (P<0.01) than control group at 14-63d and 7-63d respectively; The OD values of both two test groups were significant higher (P<0.05) than GPV attenuated vaccine groups and empty plasmid group at 21-63d and 21-49 days respectively; Though the significant difference were not detected among the three doses of intramuscular injection and the three doses of gene gun bombardment, but the effect of the 200μg group was stronger than other dosages groups in intramuscular injection groups. Results above indicated that the excellent cellular immunity effects could be induced by pcDNA-GPV-VP3 DNA vaccine be immunized by intramuscular injection and gene gun bombardment, and the efficiency of immunity with gene gun bombard is 50-200 time higher than intramuscular injection.The changes of anti-GPV IgG in the peripheral blood: The OD450 values were increased from 14 d, chalked to the highest point at 21 d and then degraded after immunization. But the titres were low.The OD values in intramuscular injection goslings (P<0.05) at 21-217days, in gene gun bombardment goslings (P<0.05) at 14-217 days in GPV attenuated vaccine goslings (P<0.05) at 21-217 days were higher or slightly higher than that in the PBS and empty plasmid goslings. Though the significant difference were not detected among the three doses of intramuscular injection and gene gun bombardment, but the effect of the 6μg group was (P<0.01) slightly higher than that other dosages groups in intramuscular injection groups and gene gun bombardment. 200μg group was stronger than other dosages groups in intramuscular injection groups. The significant difference were not detected between 3μg and 6μg, but the dosage of 3μg and 6μg were higher or slightly higher than 1μg in gene gun bombardment.The results demonstrated that pcDNA-GPV-VP3 DNA vaccine could induce goslings to produce good humoral immune responses and it showed some dose-dependent character. The titers of specific IgG of the group vaccinated by gene gun bombardment were higher than that by intramuscular injection.