RESUMEN
We designed and constructed a fuse expression gene OAAT and staphylococcal enterotoxin A (SEA) on the basis of the OAAT designed and constructed which consists of the structural protein VP1 genes from serotypes A and O FMDV, 5 major VP1 immunodominant epitopes from two genotypes of Asia1 serotype, and 3 Th2 epitopes originating from the non-structural protein, 3ABC gene and structural protein VP4 gene. The recombinant plasmids pEA was constructed using SEA as a genetic adjuvant. Expressions of target gene from the pEA in Hela cell were verified by IFA and Western blotting. The experiment of BALB/c mice immunized with the DNA vaccines showed that pA and pEA could induce simultaneously specific antibodies against serotypes A, Asia1, and O FMDV, and the highest antibody titres were found in the pEA and inactivated vaccine groups compared to pA vaccinating mice. Compared with the control, the levels of IL-2, IFN-gamma, IL-4, and IL-10 expression by splenic lymphocytes from mice immunized with pA and pEA were significantly increased. In addition, we found that the levels of IL-2, IFN-gamma and IL-4 from the mice immunized with pEA was higher than mice immunized with pA did. The results of viral challenge in guinea pigs showed the pA, pEA and inactivated vaccine provided full protection in 2/4, 2/4, 3/4, 3/4 and 4/4, 4/4 guinea pigs from challenge with FMDV O/NY00 and Asial/YNBS/58, respectively. The results demonstrated fuse protein OAAT and SEA may be potential immunoge against FMDV, furthermore, SEA may be an effective genetic adjuvant for DNA vaccine.