Effect of Nef-Deleted Pseudotyped HIV Virions Bearing an Enhanced Green Fluorescent Protein (EGFP) Gene in the env on HIV-Sensitive Transformed T Cells

For determining the actual antigenic molecules in human immunodeficiency virus type-1 (HIV-1) recognized by cytotoxic T lymphocytes (CTLs) generated among long term non-progressors (LTNP) who might gain protective immunity against HIV-1 through nef-deleted mutants, we have designed replication-defective recombinant HIV-1 particles pseudotyped with vesicular stomatitis virus glycoprotein (VSV-G), carrying an enhanced green fluorescent protein (EGFP) gene in place of the env. VSV-G pseudotyped virions had significantly augmented infectivity for both dividing and non-dividing cells, and EGFP enables single cell analysis to identify the infected cells producing viral antigen p24. These pseudotyped viral particles could also infect Herpesvirus saimiri-transformed human CD4 - T cells (HVS-T) to produce p24 antigen with or without the nef gene. Although the surface expression of CD4 and class I MHC molecules but not class II MHC', Fas and B7-2 molecules was down-modulated in T cells infected with pseudotyped virions expressing the nef gene, none of the above molecules were down-modulated in the cells infected with nef-deleted pseudotyped virions. VSV-G pseudotyped HIV-I particles encoding the EGFP gene and HSV-T cells will be useful for analyzing the actual target molecules recognized by CTLs having protective capacity against HIV-1 in vivo and thus, will open new paths for vaccine development.