Construction and characterization of recombinant fowlpox virus coexpressing HIV-1(CN) gp120 and IL-2

The acquired immunodeficiency syndrome (AIDS) has now become one of the most serious infectious disease in the world, the safe and effective AIDS vaccines would be the best tools to control the disease. Fowlpox virus has been studied recently as a potential vector for the delivery of heterologous vaccine antigen. In this study, a recombinant fowlpox virus coexpressing gp120 of Chinese prevalent HIV-1 strain and IL-2 was constructed and the cellular immune responses against HIV-1 gp120 in BALB/c mice were evaluated. Chinese vaccine strain 282E4 of fowlpox virus was used as the vector to construct the recombinant fowlpox virus (rFPV) coexpressing HIV-1 gp120 and IL-2 via homologous recombination, and the recombinant virus was identified by PCR and Western blotting. The specific DNA fragment was amplified by PCR from the genomes of rFPV. Western blotting analysis showed that HIV-1 gp120 and IL-2 was expressed not only in chicken embryo fibroblast (CEF) cells infected by rFPV, but also in mammalian cells infected by rFPV. After the recombinant fowlpox virus was inoculated into BALB/c mice, specific CTL activities in the immunized mice were detected in the spleen. The results demonstrated that rFPV had good immunogenicity and could induce BALB/c mice to produce specific cellular immunity. IL-2 played a role of immunoadjuvant and enhanced the cellular immune response. The study provides the basis for the preparation of a Chinese vaccine candidate against HIV-1.