关键词: 猪细小病毒, VP2基因, 猪圆环病毒, ORF2基因, IFN-γ基因

Abstract: Three genes encoding interferon-gamma (IFN-γ), major epitope (47-85AA) of ORF2 of PCV2 and VP2 of Porcine parvovirus were cloned and inserted into eukaryotic vector of pCI-neo, the recombinant expression plasmid of pCI-IFN-γ.ORF2.VP2 was constructed. And then the constructed plasmid was transfected into MDBK cells by lipofectamine. The expressed product was tested by Indirect Immunofluorescence and RT-PCR. The recombinant plasmid pCI-IFN-γ.ORF2.VP2 and pCI-ORF2.VP2, the control plasmid pCI-neo, PBS, the PPV inactivated vaccine and PCV2 subunit vaccine were injected into mice by intramuscular method. The lymphocyte transformation function of immuned mice was detected; In the different periods, the dynamic variation of blood T lymphocytes were assayed; PPV and PCV2 antibodies were measured too. The experimental results showed that the MDBK cells with the transfection restructuring plasmid could not only amplify the ORF2-VP2 and IFN-γ gene, but also produce green fluorescence which could be seen by Fluorescence Microscope. Expression of the specific protein was detected too. All of these were considered as a confirmation of biological activities of the expressed protein. From the seventh-day on, the splenic lymphocytes had obvious response to ConA in the group of mice immuned by pCI-IFN-γ.ORF2.VP2，which was higher than that of control and the group of mice immuned by pCI-ORF2.VP2; the number of CD3⁺CD4⁺, CD3⁺CD8⁺T lymphocytes were higher or significantly higher than that of control group and the group of mice immuned by pCI-ORF2.VP2; On the fourteenth day, the antibodies of PPV and PCV were detected. These results manifested that the pCI-IFN-γ.ORF2.VP2 effectively induced humoral and cellular immunity response in organism.

Key words: porcine parvovirus, VP2 gene, porcine circovirus type 2, ORF2 gene, IFN-γ gene