Expression of Porcine Interleukin-2 and Porcine Interleukin-6 and Their Adjuvant Effects on Gene Deleted Vaccine of Pseudorabies Virus （TK^-／gG^-／LacZ^＋）

Porcine interleukin-2 and porcine interleukin-6 cDNA sequences were cloned into the expressing vectors pET-28a and pGEX-KG respectively. They were expressed in E.coli BL21 (DE3) with high-level production. The gene deleted vaccine of pseudorabies virus Ea strain (TK-/gG-/LacZ+) was mixed with the two different purified recombinant proteins each, or both, with the doses of 2, 5 or 10 μg ml-1. Ten groups of pseudorabies negative antibody swines were immuned twice with tested vaccines with different doses, or control vaccine, respectively. The antibody titers of the test groups were detected by neutralization test, and the daily weight gains of swines were calculated and analyzed statistically. In the study, all the neutralizing antibody titers in test groups were higher than the control group, and the recombinant proteins appeared a dose dependent adjuvant effect. The tested vaccines with 2 μg ml-1 pIL-2 and with 10 μg ml-1 pIL-2/pIL-6 got significant and extremely significant differences, compared with the vaccines without pILs. The difference of the daily weight gain indicated the potential positive influence of pIL-2 and pIL-6 on immune protection.