Expression Of Bovine Ephemeral Fever Virus Glycoprotein G Gene And Bovine Interleukine-2 Gene In Recombinant Vaccinia Virus

Bovine ephemeral fever (BEF) is a disabling febrile infection of cattle and water buffalo caused by bovine ephemeral fever virus, which is widespread in many countries and areas of Asia, Africa and Australia. This disease has cause great economic losses in cattle industry' worldwide, because of its high morbidity. BEFV is a member of the family' of Rhabdovirdae. It is composed of five kinds of proteins, of which. G protein is the major protective antigen. It has demonstrated that cattle immunized with subunit vaccine based the G protein could induce protection against challenge with highly lethal virus infection.lnterleukine-2 (IL-2), secreted from helper T cell type I (Tb I), is a T-cel] growth factor (TCGF) with many biological properties. With the development of the molecular technique, recombinant IL-2 provides new method to solve the problem of vaccine with unstable or low efficiency, and has become a new type of adjuvant with bright prospect.In this study, vaccinia virus recombinants expressing G gene of BEFV alone or co-expressing G gene and IL-2 gene of bovine were constructed. The expressing level of these two kinds of proteins in recombinant virus was evaluated.Firstly, G gene from a BEFV isolate of China was amplified by RT-PCR, cloned and sequenced. The result showed that there was a T5CT sequence motif within the G gene, which could teminate the promoter function of vaccinia promoter P75. To overcome this problem. pSCP~ was constructed using a strong synthetic promoter named by P~ took place of promoter P75 in vaccinia virus transfer vector pSC 11. Then the 6 gene of BEFV was cloned into pSCP~, downstream by the promoter P~. This transfer plasmid containing G gene of BEFV was constracted and named as pSCP~ G. Another recombinant transfer plasmid containing G gene and sIl-2 gene named pSCP~GsIL-2 was constructed with the LacZ gene promoter by P~ in the pSCP~ G was substitued with BoIL-2.These two transfer plasmids were transfected on Vero cell infected with parent vaccinia virus WR swain. The recombinant virus plaque was initial screened by their colors in the presence of X-gal or by 5-Bromo-2'-deoxy-uridine and identifed by SDS-PAGE and MIT. The results demonstrated that both G protein and IL-2 could be efficiently expressed by the recombinant viruses.Earlier and higher titers of neutralizing antibodies, could be induced when rabbitsimmunized with recombinant vaccinia virus containing (1 gene of BEFV, compared with conventional inactivated oil-emulsioned vaccine. These results suggested that the recombinant vaccinia virus would become a vaccine candidate for preventing from BEF in the future.In a word, The current study would lay foundation for developing the recombinant vaccinia vaccine of BEF and studying the immuno-enhancement of JL-2 in recombinant vaccines.