Generation and characterization of HIV-1 clones chimeric for subtypes B and C nef.

The impact of human immunodeficiency virus type 1 (HIV-1) Nef on viral infectivity was evaluated by characterization of chimeric clones. Chimera with respect to the nef gene were constructed between subtypes B and C, and monitored for their replication in human peripheral blood mononuclear cells. The parental clones used were pNL432 (subtype B) and pIndie-C1 (Indian subtype C), which show considerable sequence heterogeneity in nef and distinct viral growth phenotype. While an enhancing effect of Nef on viral infectivity was noted, no significant growth difference was observed between the parental and chimeric clones. The difference in growth potential of the two subtype clones was mainly ascribable to viral sequence(s) other than nef. Our results here clearly showed that HIV-1 Nef does not significantly affect the in vitro viral infectivity in natural target cells.