Construction and tropism characterisation of recombinant viruses exhibiting HIV-1 env gene from seminal strains

Genetic differences between blood and mucosal-derived HIV-1 strains have been widely reported. As amplification of HIV-1 strains from mucosal samples including semen or saliva by co-culture has low sensitivity, we developed the construction of chimeric viruses expressing wild-type seminal HIV-1 envelope protein. Chimeric viruses were produced by co-transfection of a V1–V3 deleted pNL 43 vector and PCR fragments spanning the deleted region, amplified from HIV-1 RNA positive seminal plasma samples. After an initial testing of co-receptor usage by a tropism recombinant test, replication capacity and amplification of these recombinant viruses were assessed using PBMC. Four chimeric replicative strains, all using CXCR4 as coreceptor, were produced. The interaction between cell-free viral particles and reporter cell lines was assessed by confocal microscopy. These replicative chimeras exhibiting HIV-1 env from seminal strains represent useful tools for the in vitro study of the heterosexual transmission of HIV-1 and testing of microbicide activity.