Tracking HIV Rebound following Latency Reversal Using Barcoded HIV

Abstract

Summary HIV latency prevents cure of infection with antiretroviral therapy (ART) alone. One strategy for eliminating latently infected cells involves the induction of viral protein expression via latency-reversing agents (LRAs), allowing killing of host cells by viral cytopathic effects or immune effector mechanisms. Here, we combine a barcoded HIV approach and a humanized mouse model to study the effects of a designed, synthetic protein kinase C modulating LRA on HIV rebound. We show that administration of this compound during ART results in a delay in rebound once ART is stopped. Furthermore, the rebounding virus appears composed of a smaller number of unique barcoded viruses than occurs in control-treated animals, suggesting that some reservoir cells that would have contributed virus to the rebound process are eliminated by LRA administration. These data support the use of barcoded virus to study rebound and suggest that LRAs may be useful in HIV cure efforts.

Latency reversal plus natural killer cells diminish HIV reservoir in vivo

“…In the current study we monitored viral loads for a much longer period of ~12 weeks after ART interruption, which likely explains why we found all mice receiving SUW133 alone eventually rebounded. Another difference is the use of TKO-BLT mice in the current study, which have lower levels of endogenous immune activation compared with the NSG-BLT used in the previous study 8,58 . This diminished basal immune activation may make induction of high-level HIV expression in latently infected cells by an LRA alone more difficult to achieve, necessitating the use of a specific "kill" agent to eliminate these cells as opposed to viral cytopathic effects alone.…”

“…NK cells also delay rebound of X4-tropic barcoded HIV. Next, we investigated whether HIV-1 barcoded technology could quantify the effect that allogeneic human peripheral blood NK cells had on rebounding viral clones after ART interruption 8,45 . As such, we recently developed a genetically barcoded HIV-1 containing a 21 bp genetic barcode inserted upstream of a hemagglutinin tag in the nonfunctional vpr region of the HIV strain NL-HA 8,46 , which is an X4-tropic near full-length, replication-competent, pathogenic strain of NL4-3 (Fig.…”

“…Various latency reversing agents (LRAs) have been used to kick (or shock) infected cells out of latency and induce their death by virusinduced cytopathic effects, but a kick alone may not be sufficient in eliminating the HIV reservoir 5 . Indeed, we have previously described a synthetic bryostatin analog SUW133, which by itself reversed latency and induced the death of a subset of previously latent cells [6][7][8] , suggesting that the addition of a dedicated kill agent could further diminish the viral reservoir. Kill approaches have included immunological therapies that target HIV-infected cells by enhancing endogenous antiviral immune responses or harnessing of antibody-based or effector cell therapies (reviewed in 9 ).…”

Vpr shapes the proviral landscape and polyclonal HIV-1 reactivation patterns in cultured cells

“…Because identifying latent cells is challenging, many experimental latency systems include reporter genes and/or delete viral genes believed to be unnecessary for silencing and reactivation (33,34,52). For example, two prominent studies that used barcoded proviruses to track virus dissemination in animals used vpr-proviruses (33,52). The impact of this variation is not well understood.…”

“…This suggests that the observed effect of vpr in our in vitro system may also contribute to shaping the persistent latent reservoir in patients. If so, existing animal studies that have studied latency and reactivation using vpr-proviruses may largely be tracking the properties of proviruses that are eliminated during natural infection (52).…”