The Construction Of The First SHIV And Attenuated Vaccinia Virus-based Vaccines Targeting HIV-1 B' Subtype

We previously demonstrated that B' is the major HIV-1 genotype among paid blood donators (PBDs) in Henan and surrounding provinces in China. Here, we characterized the tat/rev/vpu/env genes of a primary B' HIV-1_02hnsmx2 Henan isolate. By sequence analysis, we found that the open reading frame for each of tat/rev/vpu/env was intact. Moreover, the env gene was found representing the typical B' virus circulating in the affecting region. The B' envelope had CCR5-tropism as it mediated cell-to-cell fusion when it was expressed in 293T cells then mixed with GHOST.CD4.CCR5 cells. We have generated a novel SHIV, named SHIV-B'whu, by replacing counterparts of SHIV_SF33 with newly obtained B' tatfrev/vpu/env genes. SHIV-B'whu maintained the phenotype of the parental HIV-1 strain and was able to replicate in peripheral blood mononuclear cells of Chinese rhesus monkeys. The new SHIV-B'whu is essential for generating a Chinese rhesus monkey model to study HIV-1 B' envelope-mediated pathogenesis, vaccine and microbicides.The rapid spread of HIV-1 in China emphasizes the urgent need to develop a prophylactic vaccine. We have recently developed a live, highly attenuated vaccinia TianTan Strain (TT.WHU.ZCI) as a vector for HIV vaccine construction. Using this vector, we have successfully constructed three HIV-1 B' vaccine candidates. The gagpol and (or) env genes of HIV-1 B' were introduced into the TT.WHU.ZCI genome using dual-promoter insertion vectors, respectively. HIV-1 Env protein was found on the surface of cells infected by rVTT-ZCIenv. Moreover, HIV-1 virus-like particles (VLP) were found in cells infected with rVTT-ZCIgagpol by EM analysis. We also determined the immunogenicity of rVTT-ZCIenv in BALB/c mice using various immunization routes and doses. We detect immune responses against HIV-1 envelope protein in mice immunized via intramusclar, subcutaneous and intradermal routes. The data indicated that we are the first to use the newly developed attentuated VTT system to construct HIV-1 vaccines. Our findings will form a solid basis for the design and construction of a new generation of vaccines specifically for use in China where the HIV-1 B' is dominant.