HPLC-Based Purification and Isolation of Potent Anti-HIV and Latency Reversing Daphnane Diterpenes from the Medicinal Plant Gnidia sericocephala (Thymelaeaceae).

Despite the success of combination antiretroviral therapy (cART), HIV persists in low- and middle-income countries (LMIC) due to emerging drug resistance and insufficient drug accessibility. Furthermore, cART does not target latently-infected CD4+ T cells, which represent a major barrier to HIV eradication. The "shock and kill" therapeutic approach aims to reactivate provirus expression in latently-infected cells in the presence of cART and target virus-expressing cells for elimination. An attractive therapeutic prototype in LMICs would therefore be capable of simultaneously inhibiting viral replication and inducing latency reversal. Here we report that Gnidia sericocephala, which is used by traditional health practitioners in South Africa for HIV/AIDS management to supplement cART, contains at least four daphnane-type compounds (yuanhuacine A (1), yuanhuacine as part of a mixture (2), yuanhuajine (3), and gniditrin (4)) that inhibit viral replication and/or reverse HIV latency. For example, 1 and 2 inhibit HIV replication in peripheral blood mononuclear cells (PBMC) by >80% at 0.08 µg/mL, while 1 further inhibits a subtype C virus in PBMC with a half-maximal effective concentration (EC50) of 0.03 µM without cytotoxicity. Both 1 and 2 also reverse HIV latency in vitro consistent with protein kinase C activation but at 16.7-fold lower concentrations than the control prostratin. Both 1 and 2 also reverse latency in primary CD4+ T cells from cART-suppressed donors with HIV similar to prostratin but at 6.7-fold lower concentrations. These results highlight G. sericocephala and components 1 and 2 as anti-HIV agents for improving cART efficacy and supporting HIV cure efforts in resource-limited regions.

Autologous IgG antibodies block outgrowth of a substantial but variable fraction of viruses in the latent reservoir for HIV-1.

In untreated HIV-1 infection, rapid viral evolution allows escape from immune responses. Viral replication can be blocked by antiretroviral therapy. However, HIV-1 persists in a latent reservoir in resting CD4+ T cells, and rebound viremia occurs following treatment interruption. The reservoir, which is maintained in part by clonal expansion, can be measured using quantitative viral outgrowth assays (QVOAs) in which latency is reversed with T cell activation to allow viral outgrowth. Recent studies have shown that viruses detected in QVOAs prior to treatment interruption often differ from rebound viruses. We hypothesized that autologous neutralizing antibodies directed at the HIV-1 envelope (Env) protein might block outgrowth of some reservoir viruses. We modified the QVOA to reflect pressure from low concentrations of autologous antibodies and showed that outgrowth of a substantial but variable fraction of reservoir viruses is blocked by autologous contemporaneous immunoglobulin G (IgG). A reduction in outgrowth of >80% was seen in 6 of 15 individuals. This effect was due to direct neutralization. We established a phylogenetic relationship between rebound viruses and viruses growing out in vitro in the presence of autologous antibodies. Some large infected cell clones detected by QVOA carried neutralization-sensitive viruses, providing a cogent explanation for differences between rebound virus and viruses detected in standard QVOAs. Measurement of the frequency of reservoir viruses capable of outgrowth in the presence of autologous IgG might allow more accurate prediction of time to viral rebound. Ultimately, therapeutic immunization targeting the subset of variants resistant to autologous IgG might contribute to a functional cure.

The African natural product knipholone anthrone and its analogue anthralin (dithranol) enhance HIV-1 latency reversal.

A sterilizing or functional cure for HIV is currently precluded by resting CD4+ T cells that harbor latent but replication-competent provirus. The "shock-and-kill" pharmacological ap-proach aims to reactivate provirus expression in the presence of antiretroviral therapy and target virus-expressing cells for elimination. However, no latency reversal agent (LRA) to date effectively clears viral reservoirs in humans, suggesting a need for new LRAs and LRA combinations. Here, we screened 216 compounds from the pan-African Natural Product Library and identified knipholone anthrone (KA) and its basic building block anthralin (dithranol) as novel LRAs that reverse viral latency at low micromolar concentrations in multiple cell lines. Neither agent's activity depends on protein kinase C; nor do they inhibit class I/II histone deacetylases. However, they are differentially modulated by oxidative stress and metal ions and induce distinct patterns of global gene expression from established LRAs. When applied in combination, both KA and anthralin synergize with LRAs representing multiple functional classes. Finally, KA induces both HIV RNA and protein in primary cells from HIV-infected donors. Taken together, we describe two novel LRAs that enhance the activities of multiple "shock-and-kill" agents, which in turn may inform ongoing LRA combination therapy efforts.

Preventive cancer screening practices in HIV-positive patients.

As patients with HIV age, they are at risk of developing non-AIDS defining malignancies. We performed a questionnaire study to evaluate colorectal and breast cancer screening among HIV-positive and HIV-negative patients seeking care from either an integrated (HIV/primary care), nonintegrated (specialized HIV), or general internal medicine clinic between August 2010 and July 2011. We performed a logistic regression to determine the odds of cancer screening. A total of 813 surveys were collected, and 762 were included in the analysis. As much as 401 were from HIV-positive patients. Patients with HIV were less likely to be current with their colorectal cancer screening (CRCS) (54.4% versus 65.0%, p=0.009); mammography rates were 24.3% versus 62.3% if done during the past year (p<0.001), and 42.0% versus 86.7% if done during the past 5 years (p<0.001). In adjusted models, the odds of colorectal cancer screening in HIV-positive patients compared to negative controls was not statistically significant (OR 0.8; 95% CI 0.5-1.3); however, HIV-positive women remained significantly less likely to be current with breast cancer screening (BCS) whether their mammogram was completed within 1 year (OR 0.1, 95% CI 0.1-0.2) or within 5 years (OR 0.1, 95% CI 0.0-0.2). Integrated care was not associated with improved screening; however, having frequent visits to a primary care physician (PCP) increased the likelihood of getting screened. BCS was lower in HIV-positive compared to HIV-negative women. Frequent visits to a PCPs improved cancer screening.