Results of a phase 1, randomized, placebo-controlled first-in-human trial of griffithsin formulated in a carrageenan vaginal gel

Safety of carrageenan-based gels as preventive microbicides: a narrative review

BACKGROUND

Carrageenan-containing gels researched for the prevention of sexually transmitted infections (STIs) have shown promising results for human papillomavirus prevention in women, but not in men. We conducted a narrative review to assess the safety of these gels for genital use.

METHODS

We searched PubMed using MeSH terms and keywords on 5 November 2023. Title/abstract of articles were screened to identify relevant ones. Full-text screening determined eligibility: empirical study evaluating safety of carrageenan-containing gel(s) for genital use.

RESULTS

Of the 125 identified records, 15 were eligible, comprising 14 (10 randomised controlled trials and 4 cohorts) unique study populations. Studies included women only (n=11), men only (n=1) or both (n=3); number of participants ranged from 4 to 6202. Safety was assessed for vaginal (n=13), penile (n=3) and anal use (n=2). Most studies assessed safety of Carraguard (53%), followed by Divine9 (14%), and one each of iota-carrageenan gel, lambda-carrageenan gel, Carvir, PC-6500 (griffithsin and carrageenan) and PC-1005 (MIV-150/zinc acetate/carrageenan). Safety assessment relied on self-report (80.0%), testing for STIs (53.3%), investigator-identified genital findings (93.3%) and/or testing for changes in genital flora (60.0%). Adverse events (AEs) were described by investigators as mostly mild, (mostly) comparable between groups, not observed and/or not significant for vaginal and penile use. Only one study, assessing anal use of carrageenan, reported a significantly higher proportion of AEs in the carrageenan compared with placebo group.

CONCLUSIONS

Carrageenan-based gels are generally well tolerated for vaginal and penile, but not anal use. Studies on carrageenan gel's safety for anal use are scarce.

Lectibodies as antivirals

Growing concerns regarding the emergence of highly transmissible viral diseases highlight the urgent need to expand the repertoire of antiviral therapeutics. For this reason, new strategies for neutralizing and inhibiting these viruses are necessary. A promising approach involves targeting the glycans present on the surfaces of enveloped viruses. Lectins, known for their ability to recognize specific carbohydrate molecules, offer the potential for glycan-targeted antiviral strategies. Indeed, numerous studies have reported the antiviral effects of various lectins of both endogenous and exogenous origins. However, many lectins in their natural forms, are not suitable for use as antiviral therapeutics due to toxicity, other unfavorable pharmacological effects, and/or unreliable manufacturing sources. Therefore, improvements are crucial for employing lectins as effective antiviral therapeutics. A novel approach to enhance lectins' suitability as pharmaceuticals could be the generation of recombinant lectin-Fc fusion proteins, termed "lectibodies." In this review, we discuss the scientific rationale behind lectin-based antiviral strategies and explore how lectibodies could facilitate the development of new antiviral therapeutics. We will also share our perspective on the potential of these molecules to transcend their potential use as antiviral agents.

Gums as Macromolecular Crowding Agents in Human Skin Fibroblast Cultures

Even though tissue-engineered medicines are under intense academic, clinical, and commercial investigation, only a handful of products have been commercialised, primarily due to the costs associated with their prolonged manufacturing. While macromolecular crowding has been shown to enhance and accelerate extracellular matrix deposition in eukaryotic cell culture, possibly offering a solution in this procrastinating tissue-engineered medicine development, there is still no widely accepted macromolecular crowding agent. With these in mind, we herein assessed the potential of gum Arabic, gum gellan, gum karaya, and gum xanthan as macromolecular crowding agents in WS1 skin fibroblast cultures (no macromolecular crowding and carrageenan were used as a control). Dynamic light scattering analysis revealed that all macromolecules had negative charge and were polydispersed. None of the macromolecules affected basic cellular function. At day 7 (the longest time point assessed), gel electrophoresis analysis revealed that all macromolecules significantly increased collagen type I deposition in comparison to the non-macromolecular crowding group. Also at day 7, immunofluorescence analysis revealed that carrageenan; the 50 µg/mL, 75 µg/mL, and 100 µg/mL gum gellan; and the 500 µg/mL and 1000 µg/mL gum xanthan significantly increased both collagen type I and collagen type III deposition and only carrageenan significantly increased collagen type V deposition, all in comparison to the non-macromolecular crowding group at the respective time point. This preliminary study demonstrates the potential of gums as macromolecular crowding agents, but more detailed biological studies are needed to fully exploit their potential in the development of tissue-engineered medicines.

HIV-1 interaction with an O-glycan-specific bacterial lectin enhances virus infectivity and resistance to neutralization by antibodies

Bacteria dysbiosis has been associated with an increased risk of HIV-1 transmission and acquisition. The prevalent idea is that bacteria dysbiosis compromises mucosal integrity and promotes inflammatory conditions to cause recruitment and activation of immune cells that harbor or are targeted by HIV-1. However, it is also possible that HIV-1 directly binds bacteria or bacterial products to impact virus infectivity and transmissibility. This study evaluated HIV-1 interactions with bacteria through glycan-binding lectins. The Streptococcal Siglec-like lectin SLBR-N, which is part of the fimbriae shrouding the bacteria surface and recognizes α2,3 sialyated O-linked glycans, was noted for its ability to enhance HIV-1 infectivity in the context of cell-free infection and cell-to-cell transfer. Enhancing effects were recapitulated with O-glycan-binding plant lectins, signifying the importance of O-glycans. Conversely, N-glycan-binding bacterial lectins FimH and Msl had no effect. SLBR-N was demonstrated to capture and transfer infectious HIV-1 virions, bind to O-glycans on HIV-1 Env, and increase HIV-1 resistance to broadly neutralizing antibodies targeting different regions of Env. Hence, this study highlights the potential contribution of O-glycans in promoting HIV-1 infection through the exploitation of O-glycan-binding lectins from commensal bacteria at the mucosa.

The Antiviral Activity of the Lectin Griffithsin against SARS-CoV-2 Is Enhanced by the Presence of Structural Proteins

Although COVID-19 transmission has been reduced by the advent of vaccinations and a variety of rapid monitoring techniques, the SARS-CoV-2 virus itself has shown a remarkable ability to mutate and persist. With this long track record of immune escape, researchers are still exploring prophylactic treatments to curtail future SARS-CoV-2 variants. Specifically, much focus has been placed on the antiviral lectin Griffithsin in preventing spike protein-mediated infection via the hACE2 receptor (direct infection). However, an oft-overlooked aspect of SARS-CoV-2 infection is viral capture by attachment receptors such as DC-SIGN, which is thought to facilitate the initial stages of COVID-19 infection in the lung tissue (called trans-infection). In addition, while immune escape is dictated by mutations in the spike protein, coronaviral virions also incorporate M, N, and E structural proteins within the particle. In this paper, we explored how several structural facets of both the SARS-CoV-2 virion and the antiviral lectin Griffithsin can affect and attenuate the infectivity of SARS-CoV-2 pseudovirus. We found that Griffithsin was a better inhibitor of hACE2-mediated direct infection when the coronaviral M protein is present compared to when it is absent (possibly providing an explanation regarding why Griffithsin shows better inhibition against authentic SARS-CoV-2 as opposed to pseudotyped viruses, which generally do not contain M) and that Griffithsin was not an effective inhibitor of DC-SIGN-mediated trans-infection. Furthermore, we found that DC-SIGN appeared to mediate trans-infection exclusively via binding to the SARS-CoV-2 spike protein, with no significant effect observed when other viral proteins (M, N, and/or E) were present. These results provide etiological data that may help to direct the development of novel antiviral treatments, either by leveraging Griffithsin binding to the M protein as a novel strategy to prevent SARS-CoV-2 infection or by narrowing efforts to inhibit trans-infection to focus on DC-SIGN binding to SARS-CoV-2 spike protein.

Carrageenan as a macromolecular crowding agent in human umbilical cord derived mesenchymal stromal cell culture

Cell sheet tissue engineering requires prolonged in vitro culture for the development of implantable devices. Unfortunately, lengthy in vitro culture is associated with cell phenotype loss and substantially higher cost of goods, which collectively hinder clinical translation and commercialisation of tissue engineered medicines. Although macromolecular crowding has been shown to enhance and accelerate extracellular matrix deposition, whilst maintaining cellular phenotype, the optimal macromolecular crowding agent still remains elusive. Herein, we evaluated the biophysical properties of seven different carrageenan molecules at five different concentrations and their effect on human umbilical cord-derived mesenchymal stromal cell morphology, viability, metabolic activity, proliferation, extracellular matrix deposition and surface marker expression. All types of carrageenan (CR) assessed demonstrated a hydrodynamic radius increase as a function of increasing concentration; high polydispersity; and negative charge. Two iota CRs were excluded from further analysis due to poor solubility in cell culture. Among the remaining five carrageenans, the lambda medium viscosity type at concentrations of 10 and 50 μg/ml did not affect cell morphology, viability, metabolic activity, proliferation and expression of surface markers and significantly increased the deposition of collagen types I, III and IV, fibronectin and laminin. Our data highlight the potential of lambda medium viscosity carrageenan as a macromolecular crowding agent for the accelerated development of functional tissue engineered medicines.

Delivery of biologics: Topical administration

Biologics are unaffordable to a large majority of the global population because of prohibitively expensive fermentation systems, purification and the requirement for cold chain for storage and transportation. Limitations of current production and delivery systems of biologics were evident during the recent pandemic when <2.5% of vaccines produced were available to low-income countries and ∼19 million doses were discarded in Africa due to lack of cold-chain infrastructure. Among FDA-approved biologics since 2015, >90% are delivered using invasive methods. While oral or topical drugs are highly preferred by patients because of their affordability and convenience, only two oral drugs have been approved by FDA since 2015. A newly launched oral biologic costs only ∼3% of the average cost of injectable biologics because of the simplified regulatory approval process by elimination of prohibitively expensive fermentation, purification, cold storage/transportation. In addition, the cost of developing a new biologic injectable product (∼$2.5 billion) has been dramatically reduced through oral or topical delivery. Topical delivery has the unique advantage of targeted delivery of high concentration protein drugs, without getting diluted in circulating blood. However, only very few topical drugs have been approved by the FDA. Therefore, this review highlights recent advances in oral or topical delivery of proteins at early or advanced stages of human clinical trials using chewing gums, patches or sprays, or nucleic acid drugs directly, or in combination with, nanoparticles and offers future directions.

An approach to rapid distributed manufacturing of broad spectrum anti-viral griffithsin using cell-free systems to mitigate pandemics

This study describes the cell-free biomanufacturing of a broad-spectrum antiviral protein, griffithsin (GRFT) such that it can be produced in microgram quantities with consistent purity and potency in less than 24 h. We demonstrate GRFT production using two independent cell-free systems, one plant and one microbial. Griffithsin purity and quality were verified using standard regulatory metrics. Efficacy was demonstrated in vitro against SARS-CoV-2 and HIV-1 and was nearly identical to that of GRFT expressed in vivo. The proposed production process is efficient and can be readily scaled up and deployed wherever a viral pathogen might emerge. The current emergence of viral variants of SARS-CoV-2 has resulted in frequent updating of existing vaccines and loss of efficacy for front-line monoclonal antibody therapies. Proteins such as GRFT with its efficacious and broad virus neutralizing capability provide a compelling pandemic mitigation strategy to promptly suppress viral emergence at the source of an outbreak.

Sustained Delivery of the Antiviral Protein Griffithsin and Its Adhesion to a Biological Surface by a Silk Fibroin Scaffold

The protein Griffithsin (Grft) is a lectin that tightly binds to high-mannose glycosylation sites on viral surfaces. This property allows Grft to potently inhibit many viruses, including HIV-1. The major route of HIV infection is through sexual activity, so an important tool for reducing the risk of infection would be a film that could be inserted vaginally or rectally to inhibit transmission of the virus. We have previously shown that silk fibroin can encapsulate, stabilize, and release various antiviral proteins, including Grft. However, for broad utility as a prevention method, it would be useful for an insertable film to adhere to the mucosal surface so that it remains for several days or weeks to provide longer-term protection from infection. We show here that silk fibroin can be formulated with adhesive properties using the nontoxic polymer hydroxypropyl methylcellulose (HPMC) and glycerol, and that the resulting silk scaffold can both adhere to biological surfaces and release Grft over the course of at least one week. This work advances the possible use of silk fibroin as an anti-viral insertable device to prevent infection by sexually transmitted viruses, including HIV-1.

From plant to cancer drug: lessons learned from the discovery of taxol

Many researchers in the natural product sciences dream of discovering a successful drug. For almost all of us, this dream will never be realized. Among the heroes of our past, though, there is a team whose efforts led to the discovery of not one but two new drugs. Dr Monroe Wall and Dr Mansukh Wani isolated and solved the structures for taxol and camptothecin, plant-based compounds that continue to play a critical role in cancer therapy today. Since the 1960s and 1970s when Wall, Wani and collaborators did their seminal work, there have been tremendous technological advances in the natural product sciences. With access to most sophisticated technology, it might be expected that the rate of discovery of new drugs from plants and other sources would have sped up. However, this has not come to pass. Why is this? Is it that the promise of new drug candidates from plant-based sources has been exhausted? Has our fascination with new technologies and with the promise of the genomics revolution caused us to stop investing effort and resources in the practices that are proven to yield success? With this Viewpoint, we share the story of taxol's discovery, highlighting critical challenges that were overcome and considering their relevance to botanical natural products drug discovery today. We hope that consideration of lessons learned from the past will help fuel success by researchers currently studying plants with the goal of discovering promising therapeutic leads.

Efficacy and safety of a self-applied carrageenan-based gel to prevent human papillomavirus infection in sexually active young women (CATCH study): an exploratory phase IIB randomised, placebo-controlled trial

Background

Carrageenan demonstrated potent anti-HPV (human papillomavirus) activity in vitro and in animal models. The Carrageenan-gel Against Transmission of Cervical Human papillomavirus trial's interim analysis (n = 277) demonstrated a 36% protective effect of carrageenan against incident HPV infections. Herein, we report the trial's final results.

Methods

In this exploratory phase IIB randomised, placebo-controlled trial, we recruited healthy women aged ≥18 years primarily from health service clinics at two Canadian Universities in Montreal. Participants were randomised (1:1) by the study coordinator (using computer-assisted block randomisation with randomly variable block sizes up to a block size of eight) to a carrageenan-based or placebo gel to be self-applied every other day for the first month and before/after intercourse. Participants, study nurses, and laboratory technicians (HPV testing and genotyping) were blinded to group assignment. At each visit (months 0, 0.5, 1, 3, 6, 9, 12), participants provided questionnaire data and a self-collected vaginal sample (tested for 36 HPV types, Linear Array). The primary outcome was type-specific HPV incidence (occurring at any follow-up visit). Intention-to-treat analyses for incidence were conducted using Cox proportional hazards regression models, including participants with ≥2 visits. Safety analyses included all participants randomised. This trial is registered with the ISRCTN registry, ISRCTN96104919.

Findings

Between Jan 16, 2013 and Sept 30, 2020, 461 participants (enrolled) were randomly assigned to the carrageenan (n = 227) or placebo (n = 234) groups. Incidence and safety analyses included 429 and 461 participants, respectively. We found 51.9% (108/208) of participants in carrageenan and 66.5% (147/221) in placebo arm acquired ≥1 HPV type (hazard ratio 0.63 [95% CI: 0.49-0.81], p = 0.0003). Adverse events were reported by 34.8% (79/227) and 39.7% (93/234) of participants in carrageenan and placebo arm (p = 0.27), respectively.

Interpretation

Consistent with the interim analysis, use of a carrageenan-based gel compared to placebo resulted in a 37% reduction in risk of incident genital HPV infections in women with no increase in adverse events. A carrageenan-based gel may complement HPV vaccination.

Funding

Canadian Institutes of Health Research, CarraShield Labs Inc.

A topical rectal douche product containing Q-Griffithsin does not disrupt the epithelial border or alter CD4+ cell distribution in the human rectal mucosa

To reduce HIV transmission, locally applied pre-exposure prophylaxis (PrEP) products for anorectal use will be important complements to oral and injectable PrEP products already available. It is critical to preserve an intact rectal epithelium and avoid an influx of mucosal HIV target cells with such product use. In this phase 1 clinical trial, we evaluated application of a topical rectal douche product containing Q-Griffithsin (Q-GRFT). Colorectal tissue samples were obtained via sigmoidoscopy at baseline, 1 and 24 h after single-dose exposure in 15 healthy volunteers. In situ staining for epithelial junction markers and CD4⁺ cells were assessed as an exploratory endpoint. A high-throughput, digitalized in situ imaging analysis workflow was developed to visualize and quantify these HIV susceptibility markers. We observed no significant differences in epithelial distribution of E-cadherin, desmocollin-2, occludin, claudin-1, or zonula occludens-1 when comparing the three timepoints or Q-GRFT versus placebo. There were also no differences in %CD4⁺ cells within the epithelium or lamina propria in any of these comparisons. In conclusion, the rectal epithelium and CD4⁺ cell distribution remained unchanged following topical application of Q-GRFT. In situ visualization of HIV susceptibility markers at mucosal sites could be useful to complement standard product safety assessments.

Recent advances in exploiting carrageenans as a versatile functional material for promising biomedical applications

Carrageenans are a group of biopolymers widely found in red seaweeds. Commercial carrageenans have been traditionally used as emulsifiers, stabilizers, and thickening and gelling agents in food products. Carrageenans are regarded as bioactive polysaccharides with disease-modifying and microbiota-modulating activities. Novel biomedical applications of carrageenans as biocompatible functional materials for fabricating hydrogels and nanostructures, including carbon dots, nanoparticles, and nanofibers, have been increasingly exploited. In this review, we describe the unique structural characteristics of carrageenans and their functional relevance. We summarize salient physicochemical features, including thixotropic and shear-thinning properties, of carrageenans. Recent results from clinical trials in which carrageenans were applied as both antiviral and antitumor agents and functional materials are discussed. We also highlight the most recent advances in the development of carrageenan-based targeted drug delivery systems with various pharmaceutical formulations. Promising applications of carrageenans as a bioink material for 3D printing in tissue engineering and regenerative medicine are systematically evaluated. We envisage some key hurdles and challenges in the commercialization of carrageenans as a versatile material for clinical practice. This comprehensive review of the intimate relationships among the structural features, unique rheological properties, and biofunctionality of carrageenans will provide novel insights into their biomedicine application potential.

An approach to rapid distributed manufacturing of broad spectrum anti-viral griffithsin using cell-free systems to mitigate pandemics

This study describes the cell-free biomanufacturing of a broad-spectrum antiviral protein, griffithsin (GRFT) such that it can be produced with consistent purity and potency in less than 24 hours. We demonstrate GRFT production using two independent cell-free systems, one plant and one microbial. Griffithsin purity and quality were verified using standard regulatory metrics. Efficacy was demonstrated in vitro against SARS-CoV-2 and HIV-1 and was nearly identical to that of GRFT expressed in vivo . The proposed production process is efficient and can be readily scaled up and deployed anywhere in the world where a viral pathogen might emerge. The current emergence of viral variants has resulted in frequent updating of existing vaccines and loss of efficacy for front-line monoclonal antibody therapies. Proteins such as GRFT with its efficacious and broad virus neutralizing capability provide a compelling pandemic mitigation strategy to promptly suppress viral emergence at the source of an outbreak.

Women for science and science for women: Gaps, challenges and opportunities towards optimizing pre-exposure prophylaxis for HIV-1 prevention

Preventing new HIV infections remains a global challenge. Young women continue to bear a disproportionate burden of infection. Oral pre-exposure prophylaxis (PrEP), offers a novel women-initiated prevention technology and PrEP trials completed to date underscore the importance of their inclusion early in trials evaluating new HIV PrEP technologies. Data from completed topical and systemic PrEP trials highlight the role of gender specific physiological and social factors that impact PrEP uptake, adherence and efficacy. Here we review the past and current developments of HIV-1 prevention options for women with special focus on PrEP considering the diverse factors that can impact PrEP efficacy. Furthermore, we highlight the importance of inclusion of female scientists, clinicians, and community advocates in scientific efforts to further improve HIV prevention strategies.

Antiviral lectin Q-Griffithsin suppresses fungal infection in murine models of vaginal candidiasis

Resistance to antifungal agents in vulvovaginal candidiasis has resulted in increasing morbidity among women globally. It is therefore crucial that new antimycotic agents are developed to counter this rising challenge. Q-Griffithsin (Q-GRFT) is a red algal lectin, manufactured in Nicotiana benthamiana. Griffithsin has well characterized broad spectrum antiviral activity and has demonstrated potent in vitro activity against multiple strains of Candida, including C. albicans. We have been working to incorporate Q-GRFT into topical microbicide products to prevent HIV-1 and HSV-2 transmission. The goal of this study was to evaluate the efficacy of a prototype Q-GRFT dosage form in prophylactic and therapeutic murine models of vaginal candidiasis, through microbiologic, histopathologic, and immune studies. In a preventive model, in comparison with infected controls, Q-GRFT treatment resulted in a lower fungal burden but did not alter the number of vaginal neutrophils and monocytes. In a therapeutic model, Q-GRFT enhanced fungal clearance when compared with infected untreated controls. Finally, histopathology demonstrated lower vaginal colonization with C. albicans following Q-GRFT treatment. Our results demonstrate that Q-GRFT has significant preventive and therapeutic activity in vaginal candidiasis offering additional benefit as a topical microbicide for prevention of HIV-1 and HSV-2 transmission.

Complexity of Viral Epitope Surfaces as Evasive Targets for Vaccines and Therapeutic Antibodies

The dynamic interplay between virus and host plays out across many interacting surfaces as virus and host evolve continually in response to one another. In particular, epitope-paratope interactions (EPIs) between viral antigen and host antibodies drive much of this evolutionary race. In this review, we describe a series of recent studies examining aspects of epitope complexity that go beyond two interacting protein surfaces as EPIs are typically understood. To structure our discussion, we present a framework for understanding epitope complexity as a spectrum along a series of axes, focusing primarily on 1) epitope biochemical complexity (e.g., epitopes involving N-glycans) and 2) antigen conformational/dynamic complexity (e.g., epitopes with differential properties depending on antigen state or fold-axis). We highlight additional epitope complexity factors including epitope tertiary/quaternary structure, which contribute to epistatic relationships between epitope residues within- or adjacent-to a given epitope, as well as epitope overlap resulting from polyclonal antibody responses, which is relevant when assessing antigenic pressure against a given epitope. Finally, we discuss how these different forms of epitope complexity can limit EPI analyses and therapeutic antibody development, as well as recent efforts to overcome these limitations.

A Highly Potent SARS-CoV-2 Blocking Lectin Protein

The COVID-19 (coronavirus disease-19) pandemic affected more than 180 million people around the globe, causing more than five million deaths as of January 2022. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the new coronavirus, has been identified as the primary cause of the infection. The number of vaccinated people is increasing; however, prophylactic drugs are highly demanded to ensure secure social contact. A number of drug molecules have been repurposed to fight against SARS-CoV-2, and some of them have been proven to be effective in preventing hospitalization or ICU admissions. Here, we demonstrated griffithsin (GRFT), a lectin protein, to block the entry of SARS-CoV-2 and its variants, Delta and Omicron, into the Vero E6 cell lines and IFNAR^–/– mouse models by attaching to the spike protein of SARS-CoV-2. Given the current mutation frequency of SARS-CoV-2, we believe that GRFT protein-based drugs will have a high impact in preventing the transmission of both the Wuhan strain as well as any other emerging variants, including Delta and Omicron variants, causing the high-speed spread of COVID-19.

Estradiol inhibits HIV-1BaL infection and induces CFL1 expression in peripheral blood mononuclear cells and endocervical mucosa

An inhibitory effect of estradiol (E2) on HIV-1 infection was suggested by several reports. We previously identified increased gene expression of actin-binding protein cofilin 1 (CFL1) in endocervix in the E2-dominated proliferative phase of the menstrual cycle. Actin cytoskeleton has an integral role in establishing and spreading HIV-1 infection. Herein, we studied in vitro effects of E2 on HIV-1 infection and on CFL1 expression to gain insight into the mechanism of HIV-1 inhibition by E2. E2 dose-dependently inhibited HIV-1_BaL infection in peripheral blood mononuclear cells (PBMCs) and endocervix. In PBMCs and endocervix, E2 increased protein expression of total CFL1 and phosphorylated CFL1 (pCFL1) and pCFL1/CFL1 ratios. LIMKi3, a LIM kinase 1 and 2 inhibitor, abrogated the phenotype and restored infection in both PBMCs and endocervix; inhibited E2-induced expression of total CFL1, pCFL1; and decreased pCFL1/CFL1 ratios. Knockdown of CFL1 in PBMCs also abrogated the phenotype and partially restored infection. Additional analysis of soluble mediators revealed decreased concentrations of pro-inflammatory chemokines CXCL10 and CCL5 in infected tissues incubated with E2. Our results suggest a link between E2-mediated anti-HIV-1 activity and expression of CFL1 in PBMCs and endocervical mucosa. The data support exploration of cytoskeletal signaling pathway targets for the development of prevention strategies against HIV-1.