Targeted immuno-antiretroviral HIV therapeutic approach to provide dual protection and boosts cellular immunity: A proof-of-concept study

Human immunodeficiency virus (HIV)-infected active and latent CCR5 expressing long-lived T-cells are the primary barrier to HIV/AIDS eradication. Broadly neutralizing antibodies and latency-reversing agents are the two most promising strategies emerging to achieve functional cure against HIV infection. Antiretrovirals (ARVs) have shown to suppress plasma viral loads to non-detectable levels and above strategies have demonstrated a functional cure against HIV infection is achievable. Both the above strategies are effective at inducing direct or immune-mediated cell death of latent HIV+ T-cells but have shown respective limitations. In this study, we designed a novel targeted ARVs-loaded nanoformulation that combines the CCR5 monoclonal antibody and antiretroviral drugs (ARV) as a dual protection strategy to promote HIV functional cure. The modified CCR5 monoclonal antibody (xfR5 mAb) surface-coated dolutegravir (DTG) and tenofovir alafenamide (TAF) loaded nanoformulation (xfR5-D+T NPs) were uniformly sized <250 nm, with 6.5 times enhanced antigen-binding affinity compared to naive xfR5 mAb, and provided prolonged DTG and TAF intracellular retention (t1/2). The multivalent and sustained drug release properties of xfR5-D+T NPs enhance the protection efficiency against HIV by approximately 12, 3, and 5 times compared to naive xfR5 mAb, D+T NP alone, and xfR5 NPs, respectively. Further, the nanoformulation demonstrated high binding-affinity to CCR5 expressing CD4+ cells, monocytes, and other HIV prone/latent T-cells by 25, 2, and 2 times, respectively. Further, the xfR5-D+T NPs during short-term pre-exposure prophylaxis induced a protective immunophenotype, i.e., boosted T-helper (Th), temporary memory (TM), and effector (E) sub-population. Moreover, treatment with xfR5-D+T NPs to HIV-infected T-cells induced a defensive/activated immunophenotype i.e., boosted naive, Th, boosted central memory, TM, EM, E, and activated cytotoxic T-cells population. Therefore, this dual-action targeted mAb-ARV loaded nanoformulation could potentially become a multifactorial/multilayered solution to achieve a "functional cure."