We report that combination bNAb immunotherapy initiated on day 3 post-infection (PI) maintained durable CD8+ T cell–mediated suppression of SHIVAD8 viremia and preinoculation levels of CD4+ T cells in 9 of 13 treated monkeys during nearly 6 yr of observation, as assessed by successive CD8+ T cell–depletion experiments. In an extension of that study, two treatment interventions (bNAbs alone or cART plus bNAbs) beginning on week 2 PI were conducted and conferred controller status to 7 of 12 monkeys that was also dependent on control mediated by CD8+ cells. However, the median time to suppression of plasma viremia following intervention on week 2 was markedly delayed (85 wk) compared with combination bNAb immunotherapy initiated on day 3 (39 wk). In both cases, the principal correlate of virus control was the induction of CD8+ T cellular immunity.

A primary goal in the development of an AIDS vaccine is the elicitation of broadly neutralizing antibodies (bNAbs) that protect against diverse HIV-1 strains. To this aim, germline-targeting immunogens have been developed to activate bNAb precursors and initiate the induction of bNAbs. While most preclinical germline-targeting HIV-1 vaccine candidates only include a single bNAb precursor epitope, an effective HIV-1 vaccine will likely require bNAbs that target multiple epitopes on Env. Here, we report a newly designed germline-targeting Env SOSIP trimer, named 3nv.2, that presents three bNAb epitopes on Env: the CD4bs, V3, and V2 epitopes. 3nv.2 forms a stable trimeric Env and binds to bNAb precursors from each of the desired epitopes. Immunization experiments in rhesus macaques and mice demonstrate 3nv.2 elicits the combined effects of its parent immunogens. Our results provide proof of concept for using a germline-targeting immunogen presenting three or more bNAb epitopes and a framework to develop improved next-generation HIV-1 vaccine candidates.

Infants born to HIV-positive mothers remain at significant risk of HIV acquisition despite maternal adherence to antiretroviral therapy, cesarean delivery, and formula feeding. Our previous study reported that initiating early antiretroviral treatment at three days post-SIV infection resulted in approximately eighty percent of pediatric virologic remission. In this study, we investigated treatment outcomes in postnatally SHIV-exposed infant macaques when early intervention was delayed by two days, as well as the mechanisms underlying virologic control. The results showed that, although initiating treatment at five days post-exposure effectively suppressed viral replication, only one of the three infant macaques achieved a sustained state of virologic remission following analytical treatment interruption. Notably, this virus-controlled infant lacked detectable virus-specific immunity, including neutralizing antibodies, cytotoxic T cell responses, and antibody-dependent cellular cytotoxicity. These findings highlight the critical importance of early treatment initiation as a key determinant of virologic control in HIV-exposed, infected infants. This study provides valuable insights for guiding early pediatric HIV intervention strategies in clinical settings.

Cholesterol-PIE12-trimer (CPT31) is a potent D-peptide HIV entry inhibitor that targets the highly conserved gp41 N-peptide pocket region. CPT31 exhibited strong inhibitory breadth against diverse panels of primary virus isolates. In a SHIV macaque model, CPT31 prevented infection from a single high-dose rectal challenge. In chronically infected animals, CPT31 monotherapy rapidly reduced viral load by ~2 logs before rebound occurred due to the emergence of drug resistance. In chronically infected animals with viremia initially controlled by combination antiretroviral therapy (cART), CPT31 monotherapy prevented viral rebound after discontinuation of cART. These data establish CPT31 as a promising new candidate for HIV prevention and treatment.