Integration features of intact latent HIV-1 in CD4+ T cell clones contribute to viral persistence

Latent intact HIV-1 proviruses persist in a small subset of long-lived CD4(+) T cells that can undergo clonal expansion in vivo. Expanded clones of CD4(+) T cells dominate latent reservoirs in individuals on long-term antiretroviral therapy (ART) and represent a major barrier to HIV-1 cure. To determine how integration landscape might contribute to latency, we analyzed integration sites of near full length HIV-1 genomes from individuals on long-term ART, focusing on individuals whose reservoirs are highly clonal. We find that intact proviruses in expanded CD4(+) T cell clones are preferentially integrated within Kruppel-associated box (KRAB) domain-containing zinc finger (ZNF) genes. ZNF genes are associated with heterochromatin in memory CD4(+) T cells; nevertheless, they are expressed in these cells under steady-state conditions. In contrast to genes carrying unique integrations, ZNF genes carrying clonal intact integrations are down-regulated upon cellular activation. Together, the data suggest selected genomic sites, including ZNF genes, can be especially permissive for maintaining HIV-1 latency during memory CD4(+) T cell expansion.

Automated summary

Latent intact HIV-1 proviruses persist in long-lived CD4(+) T cells and can undergo clonal expansion. Expanded clones of CD4(+) T cells in the latent reservoir seem to preferentially integrate within ZNF genes, which may contribute to maintaining HIV-1 latency.