Clinically relevant CCR5 editing in primary CD4+ T cells with TALEN
confers resistance to HIV-1 infection
Abstract
Today’s available therapies to treat patients infected with human
immunodeficiency virus (HIV) aim at preventing viral replication and
transmission but fail to eliminate the virus. Although transplantation
of an allogeneic CCR5Δ32 homozygous stem cell grafts provided a cure for
three patients, this approach is not considered a general therapeutic
strategy because of potential severe side effects. Conversely, genome
editing to disrupt the CCR5 locus that encodes the major HIV coreceptor
was shown to confer resistance to R5-tropic HIV strains on the cellular
level. Here, we present a clinically relevant and highly efficient
approach to produce HIV-1 resistant CD4+ T cells. After transferring
mRNA coding for CCR5-targeting TALEN into CD4+ T cells by
electroporation, up to 89% of CCR5 alleles were disrupted. Genotyping
confirmed genetic stability of the edited cell product and off-target
analyses established absence of relevant mutagenic events. When
challenging these edited T cells with R5-tropic HIV, we observed
protection in a dose-dependent manner. Functional assessments revealed
no significant differences between edited and control CD4+ T cells in
terms of proliferation capacity and their ability to secrete cytokines
upon exogenous stimuli. Overall, we successfully engineered
HIV-resistant CD4+ T cells under clinically relevant conditions, paving
the way for clinical translation.