Research About The Molecule Adjuvant Effect Of Porcine IL-2 To The PCV2 ORF2/PPV VP2 DNA Vaccine

Porcine parvovirus is one of the important pathogens of porcine reproductive disorders. PCV2 is the main cause for Pigs multiple system failure syndromes after weaned (PMWS), which clinical manifestations are weight loss, pale skin, or jaundice. Both the PPV and PCV2 are not enveloped and small genomes. Fast on the differentiation between the two organizations such as the lymph nodes is a strong tropism. The PPV infection can stimulate cells to enter S phase of cell division, thus promoting the replication of PCV2 in the cell which making the symptoms more severe PMWS. If PCV2 and or PPV infection controlling effectively, it will be significance to control the occurrence of PMWS. IL-2 which not only can promote T cell proliferation, activation through multiple links,but also can stimulate a variety of cell surface molecules expression and production of multiple cytokines such as MHCII is widely used in the study of DNA vaccine adjutants.In this experiment, the amplified VP2 gene (PPV strain SC-1) and ORF2 polypeptide gene were cloned into eukaryotic expression vector pCI-neo to construct the recombinant plasmids pCI-ORF2'-VP2. And to construct the expression plasmid pCI-IL-2-ORF2'-VP2, the porcine IL-2 gene was cloned into the eukaryotic expression vector pCI-ORF2'-VP2 through gene Linker. Then the eukaryotic expression recombinant plasmids were transfected into PK15 cells and the recombinant protein was expressed and detected by immuno-fluorescent antibody technique and ELISA directly. Healthy mice were immunized with pCI-ORF2'-VP2 and pCI-IL-2-ORF2'-VP2, pCI-neo DNA, Porcine Parvovirus vaccine and Porcine Circovirus subunit vaccine as control. Anti-PPV/PCV2 antibodies were measured by ELISA, lymphocyte proliferation activity was detected by MTT method and the dynamic monitoring of the T-lymphocyte subsets respectly. The results showed that the recombination protein can express nomally, and the specific immune responses for anti-PCV2,anti-PPV and PoIL-2 antibodies were displayed. The reactive of the splenic T lymphocytes to the ConA stimulation,immune function of inducing the CD4+, CD8+T lymphocyte and the PPV/PCV2 antibody levels of the pCI-IL-2-ORF2'-VP2 group were significantly higher than the PPV vaccine group,PCV2 vaccine group and pCI-ORF2'-VP2 group after three weeks immuned. The result indicated that the IL-2 can enhance the immunity of ORF2'/VP2 DNA vaccine as cytokine adjuvant. The results provide reference data for the new generation vaccine research of PPV and PCV2.