The major obstacle impeding human immunodeficiency virus-1 (HIV-1) eradication in antiretroviral treatment (ART) treated HIV-1 subjects is the establishment of long-lived latently infected resting CD4+ T cells. Due to the fact that no drug has been effective, the search for new drugs and combinations are a priority in the HIV cure. Treatments based on nanotechnology have emerged as an innovative and promising alternative to current and conventional therapies. In this respect, nanotechnology opens up a new door for eliminating latent HIV infection. We studied the role of G1-S4, G2-S16 and G3-S16 polyanionic carbosilane dendrimers in the context of latent HIV-1 persistence. Moreover, we study the efficiency of these dendrimers in combination with latency reversal agents (LRAs) against HIV-1 infection. J89GFP lymphocyte and THP89GFP monocyte derived cell lines latently infected with HIV-1 p89GFP were used as an in vitro model of latency for our study. Viability assays by 3-(4-5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) were performed to determine the working concentrations of dendrimers and LRAs. Both cell lines were treated with G1-S4, G2-S16 and G3-S16 either alone or in combination with bryostatin (BRY), romidepsin (RMD) or panobinostat (PNB) for 24 and 48 h. The expression pattern of GFP was measured by flow cytometry and referred as measure of viral reactivation. The combination treatment of the dendrimers with the protein kinase C (PKC) agonist did not modify the antilatency activity in J89GFP lymphocyte cell line. Interestingly enough, G3-S16 dendrimer alone and its combination with BRY, RMD or PNB showed a significant increased expression of GFP in the THP89GFP monocyte cell line. We showed for the first time that nanoparticles, in this case, G3-S16 anionic carbosilan dendrimer may play an important role in new treatments against HIV-1 infection.

Development of new, safe, and effective microbicides to prevent human immunodeficiency virus HIV sexual transmission is needed. Unfortunately, most microbicides proved ineffective to prevent the risk of HIV-infection in clinical trials. We are working with G2-S16 polyanionic carbosilane dendrimer (PCD) as a new possible vaginal topical microbicide, based on its short reaction times, wide availability, high reproducibility, and quantitative yields of reaction. G2-S16 PCD exerts anti-HIV activity at an early stage of viral replication, by blocking gp120/CD4/CCR5 interaction, and providing a barrier against infection for long periods of time. G2-S16 PCD was stable at different pH values, as well as in the presence of seminal fluids. It maintained the anti-HIV activity against R5/X4 HIV over time, did not generate any type of drug resistance, and retained the anti-HIV effect when exposed to semen-enhanced viral infection. Importantly, G2-S16 PCD did not modify vaginal microbiota neither in vitro or in vivo. Histopathological examination did not show vaginal irritation, inflammation, lesions, or damage in the vaginal mucosa, after administration of G2-S16 PCD at different concentrations and times in female mice and rabbit animal models. Based on these promising data, G2-S16 PCD could become a good, safe, and readily available candidate to use as a topical vaginal microbicide against HIV.

Sequential immunization is a promising approach to elicit broadly neutralizing antibodies (bNAbs) against the HIV-1 Envelope (Env). However, available protocols are inefficient and involve multiple immunizations over long periods of time. Here, we present WIN332, a new engineered Env immunogen that induces a new class of Asn332-glycan-independent antibodies to the conserved V3-glycan epitope of Env with low inhibitory activity indicative of a neutralization activity after a single bolus immunization in nonhuman primates. WIN332 binds to precursors of canonical human Asn332-glycan-dependent (type-I) V3-glycan bNAbs but also of a first-of-its-class Asn332-glycan-independent (type-II) V3-glycan bNAb. A single immunization elicits low inhibitory serum and monoclonal antibodies that are boosted and affinity matured with a heterologous immunogen. Electron microscopy polyclonal epitope mapping analysis of serum antibodies, antibody cloning and cryogenic electron microscopy analysis reveals that WIN332 elicits Asn332-glycan-independent antibodies with striking sequence and binding similarities with the most potent human type-I and type-II V3-glycan bNAbs. Thus, WIN332 is a promising vaccine candidate to streamline V3-glycan bNAb elicitation.

Human immunodeficiency virus (HIV-1) is still a major problem, not only in developing countries but is also re-emerging in several developed countries, thus the development of new compounds able to inhibit the virus, either for prophylaxis or treatment, is still needed. Nanotechnology has provided the science community with several new tools for biomedical applications. G2-S16 is a polyanionic carbosilane dendrimer capable of inhibiting HIV-1 in vitro and in vivo by interacting directly with viral particles. One of the main barriers for HIV-1 eradication is the reservoirs created in primoinfection. These reservoirs, mainly in T cells, are untargetable by actual drugs or immune system. Thus, one approach is inhibiting HIV-1 from reaching these reservoir cells. In this context, macrophages play a main role as they can deliver viral particles to T cells establishing reservoirs. We showed that G2-S16 dendrimer is capable of inhibiting the infection from infected macrophages to healthy T CD4/CD8 lymphocytes by eliminating HIV-1 infectivity inside macrophages, so they are not able to carry infectious particles to other body locations, thus preventing the reservoirs from forming.