Pre-clinical development as microbicide of zinc tetra-ascorbo-camphorate, a novel terpenoid derivative: potent in vitro inhibitory activity against both R5- and X4-tropic HIV-1 strains without significant in vivo mucosal toxicity

In vitro inhibitory activity against HPV of the monoterpenoid zinc tetra-ascorbo-camphorate

Zinc tetra-ascorbo-camphorate (or drug "C14") is a synthetic monoterpenoid derivative that has potent anti-HIV-1 activity in vitro. In this study, we evaluated the in vitro antiviral properties of C14 against human papillomavirus (HPV). Inhibition assay of HPV-16-pseudovirus (PsVs) adsorption on COS-7 cells by C14 was used. C14 inhibited HPV-16-PsVs adsorption with IC₅₀ ranging between 2.9 and 8.3 μM and therapeutic indexes between >410 to >3,300. Pretreatment of COS-7 cells with C14 before addition of HPV-16-PsV was associated with more potent anti-HPV activity than simultaneous deposition on COS-7 of HPV-16-PsV and C14, suggesting that C14 is more effective in preventing HPV attachment to target cells than post-HPV adsorption viral events. Overall, these in vitro studies suggest that the monoterpenoid zinc tetra-ascorbo-camphorate molecule may be suitable for further clinical evaluations as potential microbicide or therapeutic drug.

The Potential of Sub-Saharan African Plants in the Management of Human Immunodeficiency Virus Infections: A Review

Acquired immunodeficiency syndrome, caused by human immunodeficiency virus (HIV), is a leading cause of mortality and morbidity in Sub-Saharan Africa, particularly in Southern Africa. Phytomedicines are an integral part of African health care. The Southern African flora is composed of at least 23 400 taxa. Despite this richness, only a handful of botanical products have been assessed for activities against HIV. This study aimed to summarize the potential of Sub-Saharan African plants, based on their composition and the established bioactivities, as sources of agents to manage HIV symptoms and as retroviral therapy. At least 109 plant species from 42 families and 94 genera that are found in Southern Africa were shown to have potential or actual activities against HIV. Only 12 of these plant species from 6 families and 10 genera were shown to harbour anti-HIV properties. Phytochemicals that include β-sitosterols, terpenoids, glycosides, saponins, flavonoids, triterpenoids, tannins and alkaloids, which harbour anti-HIV properties, were found to have a near cosmopolitan presence across the plant families in the region. Bioactivities of multiple phytochemicals are comparable to those for standard allopathic antiretroviral drugs. Research to determine the anti-HIV activities of the identified and other plants, including clinical trials, is long overdue.

Adaptive HIV-specific B cell-derived humoral immune defenses of the intestinal mucosa in children exposed to HIV via breast-feeding

Background

We evaluated whether B cell-derived immune defenses of the gastro-intestinal tract are activated to produce HIV-specific antibodies in children continuously exposed to HIV via breast-feeding.

Methods

Couples of HIV-1-infected mothers (n = 14) and their breastfed non HIV-infected (n = 8) and HIV-infected (n = 6) babies, and healthy HIV-negative mothers and breastfed babies (n = 10) as controls, were prospectively included at the Complexe Pédiatrique of Bangui, Central African Republic. Immunoglobulins (IgA, IgG and IgM) and anti-gp160 antibodies from mother’s milk and stools of breastfed children were quantified by ELISA. Immunoaffinity purified anti-gp160 antibodies were characterized functionally regarding their capacity to reduce attachment and/or infection of R5- and X4- tropic HIV-1 strains on human colorectal epithelial HT29 cells line or monocyte-derived-macrophages (MDM).

Results

The levels of total IgA and IgG were increased in milk of HIV-infected mothers and stools of HIV-exposed children, indicating the activation of B cell-derived mucosal immunity. Breast milk samples as well as stool samples from HIV-negative and HIV-infected babies exposed to HIV by breast-feeding, contained high levels of HIV-specific antibodies, mainly IgG antibodies, less frequently IgA antibodies, and rarely IgM antibodies. Relative ratios of excretion by reference to lactoferrin calculated for HIV-specific IgA, IgG and IgM in stools of HIV-exposed children were largely superior to 1, indicating active production of HIV-specific antibodies by the intestinal mucosa. Antibodies to gp160 purified from pooled stools of HIV-exposed breastfed children inhibited the attachment of HIV-1NDK on HT29 cells by 63% and on MDM by 77%, and the attachment of HIV-1JRCSF on MDM by 40%; and the infection of MDM by HIV-1JRCSF by 93%.

Conclusions

The intestinal mucosa of children exposed to HIV by breast-feeding produces HIV-specific antibodies harbouring in vitro major functional properties against HIV. These observations lay the conceptual basis for the design of a prophylactic vaccine against HIV in exposed children.

Partial inactivation of CCR5- and CXCR4- tropic HIV-1 by human urine

Human urine has been poorly investigated with regard to infection with human immunodeficiency virus (HIV). Here, we have studied the anti-infective functional properties of human urine against HIV. The effect of fresh urine pools on CCR5- and CXCR4-tropic HIV-1 was evaluated by using four in vitro mucosal models: reduction of infectivity of urine-treated HIV-1 particles, HIV-1 attachment to immature monocyte-derived dendritic cells (iMDDC), transfer of HIV-1 particles from iMDDC to autologous CD4 T cells, and HIV-1 transcytosis through epithelial cells. Human urine partially disrupted both CCR5- and CXCR4-tropic HIV-1 particles, moderately decreased the adsorption of HIV-1 on dendritic cells, and partially decreased the transfer of HIV-1 particles from dendritic cells to autologous T cells. These findings demonstrate partial inactivation of HIV infectivity and suggest that voiding urine after coitus could play a potential role in reducing the risk of HIV infection by both mechanically flushing out and neutralizing the infectivity of HIV-1 particles present in the genital tract.

Potent in vitro inactivation of both free and cell-associated CCR5- and CXCR4-tropic HIV-1 by common commercial soap bars from South Africa

We showed herein the potent virucidal effect of soap and water solutions against both CCR5-tropic and CXCR4-tropic cell-free HIV-1 strains, and cytotoxicity for HIV-1-infected lymphocytes during short incubation durations, ranging from 30 seconds to 2 minutes. These observations indicate a rapid inhibitory effect of soap and water on viral infectivity.

In vitro synergistic activity against CCR5-tropic HIV-1 with combinations of potential candidate microbicide molecules HHA, KRV2110 and enfuvirtide (T20)

OBJECTIVES

To block the different mechanisms of HIV mucosal transmission, it is likely that use of several microbicide molecules will lead to the best protection against HIV transmission. Indeed, the combination of microbicides with complementary mechanisms of action is expected to increase the antiviral potency of the formulation.

METHODS

The gp120-interacting plant lectin HHA ('Hippeastrum hybrid agglutinin'), the non-nucleoside reverse transcriptase inhibitor KRV2110 and the fusion inhibitor enfuvirtide (T20) were combined in 12 drug associations by using the Ray combination design method. Their activity against HIV-1(BaL) was assessed by the lymphocyte infectivity reduction assay and by the single-cycle BaL pseudovirus (PV) assay. In addition, their cell tolerance was evaluated for HEC-1 and HeLa epithelial cell lines, both originating from genital tissue.

RESULTS

All evaluated combinations showed synergistic activity in both lymphocyte infectivity reduction and single-cycle BaL PV assays. The combination HHA + KRV2110 resulted in the highest cell viability, whereas the combinations including T20 exhibited a dose-dependent decrease in cell viability, demonstrating the differential tolerance of epithelial cell lines to the combinations.

CONCLUSIONS

These observations provide a rational basis for in vitro testing of microbicide candidate molecule combinations, including anti-HIV-1 and cytotoxic cellular assays.

Early events in vaginal HIV transmission: implications in microbicide development

In vitro models for HIV crossing through mucosae include direct infection of epithelial cells, transcytosis through epithelial cells, epithelial transmigration of infected donor cells, uptake by intraepithelial dendritic cells, and circumvention of the epithelial barrier through physical breaches. Mucosal crossing of HIV for further reaching of the submucosal target cells (macrophages, lymphocytes and dendritic cells) may be modulated by supraepithelial factors, such as seminal complement components (opsonized HIV), by epithelial factors released in the submucosal microenvironment, such as antimicrobial soluble factors, cytokines and chemokines, and by the potent intraepithelial and submucosal innate immunity. Poor understanding of the subtle and complex orchestration of the numerous virus and cell factors involved in HIV mucosal crossing renders the design of effective microbicide formulations difficult. Thus, there is currently no clear relationship between the success of preclinical development of microbicide formulations, using the available assays of anti-HIV efficacy and mucosal toxicity, and its efficacy against HIV acquisition in women enrolled in a large-scale Phase III trial. In addition, the proof of concept that a microbicide formulation may be efficient outside the laboratory has not yet been clearly demonstrated. Finally, there is an urgent need to better understand and modelize the early events occurring during the first hours of HIV contact with the female genital mucosae, especially considering the enormous gaps of knowledge in the understanding of the mechanisms of HIV mucosal crossing through female genital mucosae.

HMGB1-dependent triggering of HIV-1 replication and persistence in dendritic cells as a consequence of NK-DC cross-talk

Background

HIV-1 has evolved ways to exploit DCs, thereby facilitating viral dissemination and allowing evasion of antiviral immunity. Recently, the fate of DCs has been found to be extremely dependent on the interaction with autologous NK cells, but the mechanisms by which NK-DC interaction controls viral infections remain unclear. Here, we investigate the impact of NK-DC cross-talk on maturation and functions of HIV-infected immature DCs.

Methodology/Principal Findings

Immature DCs were derived from primary monocytes, cultured in the presence of IL-4 and GM-CSF. In some experiments, DCs were infected with R5-HIV-1_BaL or X4-HIV-1_NDK, and viral replication, proviral HIV-DNA and the frequency of infected DCs were measured. Autologous NK cells were sorted and either kept unstimulated in the presence of suboptimal concentration of IL-2, or activated by a combination of PHA and IL-2. The impact of 24 h NK-DC cross-talk on the fate of HIV-1-infected DCs was analyzed. We report that activated NK cells were required for the induction of maturation of DCs, whether uninfected or HIV-1-infected, and this process involved HMGB1. However, the cross-talk between HIV-1-infected DCs and activated NK cells was functionally defective, as demonstrated by the strong impairment of DCs to induce Th1 polarization of naïve CD4 T cells. This was associated with the defective production of IL-12 and IL-18 by infected DCs. Moreover, the crosstalk between activated NK cells and HIV-infected DCs resulted in a dramatic increase in viral replication and proviral DNA expression in DCs. HMGB1, produced both by NK cells and DCs, was found to play a pivotal role in this process, and inhibition of HMGB1 activity by glycyrrhizin, known to bind specifically to HMGB1, or blocking anti-HMGB1 antibodies, abrogated NK-dependent HIV-1 replication in DCs.

Conclusion

These observations provide evidence for the crucial role of NK-DC cross-talk in promoting viral dissemination, and challenge the question of the in vivo involvement of HMGB1 in the triggering of HIV-1 replication and replenishment of viral reservoirs in AIDS.