Lentiviral delivery of short hairpin RNAs protects CD4 T cells from multiple clades and primary isolates of HIV

SK Lee, DM Dykxhoorn, P Kumar, S Ranjbar, E Song… - Blood, 2005 - ashpublications.org
SK Lee, DM Dykxhoorn, P Kumar, S Ranjbar, E Song, LE Maliszewski…
Blood, 2005ashpublications.org
Viral heterogeneity is a major hurdle for potential therapeutic use of RNA interference
(RNAi) against HIV-1. To determine the extent of RNAi tolerance to mutations, we tested 3
viral target sites with differing propensity for mutations: a highly variable rev sequence, a gag
sequence conserved only among clade B isolates, and a vif sequence highly conserved
across clades. Lentiviral expression of all 3 shRNAs inhibited replication of the homologous
HIVIIIB strain. However, they differed in their ability to protect primary CD4 T cells against …
Abstract
Viral heterogeneity is a major hurdle for potential therapeutic use of RNA interference (RNAi) against HIV-1. To determine the extent of RNAi tolerance to mutations, we tested 3 viral target sites with differing propensity for mutations: a highly variable rev sequence, a gag sequence conserved only among clade B isolates, and a vif sequence highly conserved across clades. Lentiviral expression of all 3 shRNAs inhibited replication of the homologous HIVIIIB strain. However, they differed in their ability to protect primary CD4 T cells against multiple isolates within and across HIV clades. The least conserved rev sequence inhibited only 2 of 5 clade B isolates. The gag sequence (conserved within clade B) protected 5 of 5 clade B isolates but not other clade viruses with 2 or 3 mutations in the central region. In contrast, the vif sequence, which was conserved across clades except for single mutations at positions 14 and 17, inhibited viruses from 5 different clades. Moreover, siRNAs with introduced mutations at sites of gag sequence polymorphisms showed reduced antiviral activity, whereas mutations in vif siRNA only modestly decreased silencing. Thus, although 1 or 2 mutations at peripheral sites are tolerated, mutations in the central target cleavage region abolish RNAi activity.
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