Construction of recombinant swinepox viruses and expression of the classical swine fever virus E2 protein

To explore the swinepox virus (SPV) as a potential live vector for immuniza tion. a vector was developed for the construction of a recombinant SPV carr ying foreign genes. In this system, a foreign gene placed under the strong vaccinia virus promoter P-11 can be inserted into the viral thymidine kinas e (TK) gene, and the recombinant virus can be isolated in a non-selective m edium by the co-expression of E. coli lacZ gene. Compared with the wild typ e virus, the TK-recombinant SPV showed a modest level of attenuation in por cine cells while more attenuation was observed in monkey or human cells. Us ing this system, a recombinant virus expressing the E? glycoprotein of clas sical swine fever virus (CSFV) was produced. Engineered with the gX signal sequence of the pseudorabies virus, and transmembrane domain of E2, the E2 protein was expressed as a dimeric form in the cytoplasm of the infected ce lls. (C) 2001 Elsevier Science B.V. All rights reserved.