Porcine IL-12 plasmid as an adjuvant improves the cellular and humoral immune responses of DNA vaccine targeting transmissible gastroenteritis virus spike gene in a mouse model

LI, Xunliang; LI, Pengchong; CAO, Liyan; BAI, Yunyun; CHEN, Huijie; LIU, He; REN, Xiaofeng; LI, Guangxing

Six-week-old Kunming mice (Harbin Veterinary Research Institute) were divided into six groups (Table 1 ) and injected with 50 µl 0.8% lidocaine hydrochloride (27 gauge needles) in the medial vastus muscle. After 15 min, the mice were immunized with 100 µg of pVAX1-(TGEV-S1), pVAX1-(pIL-12), pVAX1-(TGEV-S1) plus pVAX1-(pIL-12) (100 µg each), inactivated TGEV vaccine (vaccine control group; produced by Chengdu TECBOND Biological Products Co., Ltd., Chengdu, China), pVAX1 (empty vector control), or PBS (no treatment control). A total of three doses of immunization were given to each mouse from all groups at 2-week intervals. Four mice per group were euthanized at 0, 7, 14, 21, 28, 35, and 42 days after first immunization. Serum samples Experimental groups and cytokine levels. The six groups include pVAX1-(pIL-12) (A), pVAX1-(TGEV-S1) (B), pVAX1-(TGEV-S1) plus pVAX1-(pIL-12) (C), inactivated TGEV vaccine (D), PBS (E), and pVAX1 (F). Immunizing dose, vaccine category, and number of mice are indicated. The levels of IFN-γ and IL-4 were detected at 42 dpi with ELISA kits, a) P<0.01 (highly significant) as compared with other groups.