Targeted Nanocarriers for HIV Therapy

Abstract

Highly active antiretroviral therapy (HAART) can successfully suppress HIV-1 replication in plasma to undetectable levels, but is not capable of eradicating the virus from long-live cellular reservoirs. The latent reservoir for HIV-1 is sustained by the longevity and proliferative capacity of resting CD4 T cells containing HIV in a highly suppressed state, rendering the infection invisible to the immune system. Numerous approaches are aimed at diminishing these latent HIV reservoirs, such as early initiation of HAART, or reactivation of latent virus by use of latency reversing agents (LRAs). However, none has yet been proven effective in actually reducing the reservoir in vivo. A synergistic approach will likely be needed to deplete the reservoir and establish a cure. In addition, HIV persistence in some anatomical sites has been attributed to lower concentrations of anti-HIV drugs. In this work, we focused on developing targeted nanocarriers (NCs) to deliver synergistic anti-HIV drugs to cellular or anatomical viral reservoirs. One aim of our work is to deliver antiretroviral drugs (ARVs) to the gut-associated lymphoid tissue (GALT), a major sanctuary site for HIV infection. The α4β7 integrin gut homing receptor leads to migration of infected cells to the GALT and facilitates HIV infection. We developed a core-shell nanoparticle incorporating the α4β7 monoclonal antibody (mAb) as a dual-functional ligand for selectively targeting a protease inhibitor to gut-homing T cells in the GALT while simultaneously blocking HIV infection. This targeted NC showed specific binding to α4β7+ CD4 T lymphocytes from rhesus macaque ileum and higher levels of accumulation in α4β7+ cells from the small intestine when administered in mice. A second aim of our work is to deliver mechanistically distinct LRAs to reactivate CD4 T cells in the lymph nodes. We screened a variety of LRAs that were incorporated into NCs through different loading strategies, and determined LRA combinations that displayed synergistic latency reversal and low cytotoxicity in both human T cell line model and CD4+ T cells from HIV-infected patients under suppressive HAART. Our targeted NCs demonstrated long-acting and selective activation of CD4+ T cells in the mice lymph nodes and significantly reduced local toxicity compared to free drug. Our NCs for T cell and lymphatic tissue targeting also show promise in delivering other types of anti-HIV agents, vaccines, and immune-modulating drugs for many biomedical applications.