EXPRESSION OF A TAT-INDUCIBLE HERPES-SIMPLEX VIRUS THYMIDINE KINASE GENE PROTECTS ACYCLOVIR-TREATED CD4 CELLS FROM HIV-1 SPREAD BY CONDITIONAL SUICIDE AND INHIBITION OF REVERSE TRANSCRIPTION

Cellular expression of the herpes simplex virus type 1 thymidine kinas e (HSV1-TK) gene promotes cell death in the presence of specific nucle oside analog substrates such as acyclovir (ACV). We have repor?ed that : lymphoid CD4(+) cells harboring an HSV1-TK gene, under the transcrip tional control of the HIV-1 long terminal repeal (HUT-TK), are complet ely protected from HIV-1 spread in the presence of 10 mu M ACV. In thi s report we clarify the efficiency, generality, and mechanism of this protective effect. We show that the protection from HIV-1 spread in HU T-TK cells obtains from both an inhibition of HIV reverse transcriptio n by ACV metabolites and an HIV-induced and ACV-dependent cell killing . We also demonstrate that monocytic cells harboring the HIV-1-inducib le HSV1-TK gene are protected from HIV spread in the presence of ACV. These observations facilitate the design of therapeutic strategies to limit HIV replication based on HSV1-TK expression. (C) 1995 Academic P ress, Inc.