INTRACELLULAR IMMUNIZATION AGAINST HIV-1 INFECTION OF HUMAN T-LYMPHOCYTES - UTILITY OF ANTI-REV SINGLE-CHAIN VARIABLE FRAGMENTS

Genetic therapy offers a potentially promising approach with which to combat human immunodeficiency virus type 1 (HIV-1) infections. Several modalities, using protein- and RNA-based systems, have recently been shown to inhibit HIV-1 replication. A single-chain variable fragment ( SFv), constructed from the cDNA of a monoclonal antibody to the HIV-1 regulatory protein Rev, has been demonstrated to potently inhibit HIV- 1 replication, when expressed intracellularly in an epithelial cell-li ne (HeLa-CD4). Murine retroviral shuttle vectors, which express the an ti-Rev SFv moiety, have now been constructed. HIV-1 infection was dram atically inhibited in human T-lymphocytic cell-lines, CEM and Sup-T1, transduced with these anti-Rev SFv-expressing vectors. This resistance to high levels of HIV-1 expression was demonstrated in both mixed pop ulations and clones of these cells. Of further potential clinical sign ificance, HIV-1 infection was also potently inhibited in human periphe ral blood mononuclear cells (PBMC), transduced with retroviral vectors expressing the anti-Rev SFv molecule. These data suggest that intrace llular expression of anti-Rev SFvs, or related approaches, may be util ized as genetic therapy, or intracellular immunization, for HIV-1 infe ctions in vivo.