Self-Inactivating Lentivirus Vector for Safe and Efficient In Vivo Gene Delivery

TLDR

In vivo transduction of nondividing cells by HIV‑1‑based vectors yields stable transgene expression for months, yet raises safety concerns. The study introduces a self‑inactivating HIV‑1 vector with a 400‑nt deletion in the 3′ long terminal repeat. The deletion removes the TATA box, abolishing LTR promoter activity while preserving vector titers and in‑vitro transgene expression. The self‑inactivating vector transduced neurons in vivo as efficiently as full‑length LTR vectors, markedly improving biosafety by reducing replication‑competent virus risk and recombination with wild‑type HIV, and enhancing performance by eliminating transcriptional interference and enabling stricter tissue‑specific or regulatable designs.

Abstract

ABSTRACT In vivo transduction of nondividing cells by human immunodeficiency virus type 1 (HIV-1)-based vectors results in transgene expression that is stable over several months. However, the use of HIV-1 vectors raises concerns about their safety. Here we describe a self-inactivating HIV-1 vector with a 400-nucleotide deletion in the 3′ long terminal repeat (LTR). The deletion, which includes the TATA box, abolished the LTR promoter activity but did not affect vector titers or transgene expression in vitro. The self-inactivating vector transduced neurons in vivo as efficiently as a vector with full-length LTRs. The inactivation design achieved in this work improves significantly the biosafety of HIV-derived vectors, as it reduces the likelihood that replication-competent retroviruses will originate in the vector producer and target cells, and hampers recombination with wild-type HIV in an infected host. Moreover, it improves the potential performance of the vector by removing LTR sequences previously associated with transcriptional interference and suppression in vivo and by allowing the construction of more-stringent tissue-specific or regulatable vectors.