Cellular immune responses of BALB/c mice induced by intramuscular injection of PRRSV-ORF5 DNA vaccine with different doses

Abstract

BALB/c mice were immunized with 50 µg, 100 µg, 200 µg of pcDNA-PRRSV-ORF5 DNA vaccine respectively by intramuscular injection, with PBS and pcDNA3.1(+) as controls. Fluorescence activated cell Sorter (FACS) was used to detect the number of CD⁺₄ and CD⁺₈ T-lymphocytes. T-lymphocyte proliferation test was used to detect proliferation of the T-lymphocyte cells in peripheral blood lymphocytes of mice vaccinated with pcDNA-PRRSV-ORF5 DNA vaccine. The results showed that the difference in ConA response to T-lymphocytes in blood was highly significant between all experimental groups and the control group (P<0.01). The number of CD₄⁺ T-lymphocytes in experimental groups was significantly higher than that of the control group 7 d after vaccination. The number of CD₈⁺ T-lymphocytes in the experimental groups was higher than that of the control group 28 d after vaccination. Mice immunized with a higher dose (200 µg) of DNA vaccine demonstrated higher cellular immune response than those immunized with a lower dose (100 µg, 50 µg) of DNA vaccine. The results demonstrated that pcDNA-PRRSV-ORF5 DNA vaccine could induce a good cellular immune response which may be dose-dependent.

Key words： PRRSV; ORF5 DNA vaccine; cellular immune response; mice

Acknowledgements

This work was supported by Sichuan Bio-tech Project (No. 01NG018-03), the National State Key Program Project of Science and Technology (No. 2004BA901A03), Program for New Century Excellent Talents in University, Ministry of Education, China (No. NCET-04-0906).

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