ABSTRACT
Nonhormonal products for on-demand contraception are a global health technology gap; this unmet need motivated us to pursue the use of sperm-binding monoclonal antibodies to enable effective on-demand contraception. Here, using the cGMP-compliant Nicotiana-expression system, we produced an ultrapotent sperm-binding IgG antibody possessing 6 Fab arms per molecule that bind a well-established contraceptive antigen target, CD52g. We term this hexavalent antibody "Fab-IgG-Fab" (FIF). The Nicotiana-produced FIF had at least 10-fold greater sperm-agglutination potency and kinetics than the parent IgG, while preserving Fc-mediated trapping of individual spermatozoa in mucus. We formulated the Nicotiana-produced FIF into a polyvinyl alcohol-based water-soluble contraceptive film and evaluated its potency in reducing progressively motile sperm in the sheep vagina. Two minutes after vaginal instillation of human semen, no progressively motile sperm were recovered from the vaginas of sheep receiving FIF Film. Our work supports the potential of multivalent contraceptive antibodies to provide safe, effective, on-demand nonhormonal contraception.
Subject(s)
Antibodies, Monoclonal/pharmacology , Contraception/methods , Spermatozoa/immunology , Administration, Intravaginal , Animals , Antibodies/immunology , Contraceptive Agents/pharmacology , Female , Humans , Immunoglobulin Fab Fragments/pharmacology , Immunoglobulin G/pharmacology , Male , Models, Animal , Sheep , Sperm MotilityABSTRACT
BACKGROUND: With an unplanned pregnancy rate of 50% or more in many countries, there is an urgent need for contraceptives that are more accessible and acceptable. To meet the growing demand for new contraceptives, ZabBio developed ZB-06, a vaginal film containing HC4-N, a human contraceptive antibody that inactivates sperm. OBJECTIVE: This study aimed to assess the potential contraceptive activity of the ZB-06 film using a surrogate assessment for contraceptive efficacy, the postcoital test. We also assessed clinical safety of film use among healthy heterosexual couples. Serum, cervical mucus, and vaginal fluid HC4-N antibody concentrations and sperm agglutination potency were determined after single film use. Changes in the concentration of soluble proinflammatory cytokines and vaginal Nugent score after film use were measured as subclinical safety endpoints. STUDY DESIGN: This was a phase 1, first-in-woman, open-label, proof-of-concept, postcoital test and safety study. RESULTS: A total of 20 healthy women were enrolled in the study, and 8 heterosexual couples completed all study visits. The product was safe for both female participants and their male sexual partners. The postcoital test performed on ovulatory cervical mucus at baseline (no product use) revealed a mean of 25.9 (±30.6) progressively motile sperm per high-power field. After use of a single ZB-06 film before intercourse, this number dropped to 0.04 (±0.06) progressively motile sperm per high-power field (P<.0001). At the follow-up postcoital test visit approximately 1 month later (no product use), a mean of 47.4 (±37.4) progressively motile sperm per high-power field was observed, indicating contraceptive reversibility. CONCLUSION: A single dose of the ZB-06 film applied before intercourse was safe and met efficacy surrogate benchmarks of excluding progressively motile sperm from ovulatory cervical mucus. These data indicate that ZB-06 is a viable contraceptive candidate warranting further development and testing.
Subject(s)
Contraceptive Devices, Female , Spermatocidal Agents , Pregnancy , Humans , Male , Female , Contraceptive Agents , Spermatocidal Agents/pharmacology , Semen , VaginaABSTRACT
BACKGROUND: Although several experimental therapeutics for Ebola virus disease (EVD) have been developed, the safety and efficacy of the most promising therapies need to be assessed in the context of a randomized, controlled trial. METHODS: We conducted a trial of four investigational therapies for EVD in the Democratic Republic of Congo, where an outbreak began in August 2018. Patients of any age who had a positive result for Ebola virus RNA on reverse-transcriptase-polymerase-chain-reaction assay were enrolled. All patients received standard care and were randomly assigned in a 1:1:1:1 ratio to intravenous administration of the triple monoclonal antibody ZMapp (the control group), the antiviral agent remdesivir, the single monoclonal antibody MAb114, or the triple monoclonal antibody REGN-EB3. The REGN-EB3 group was added in a later version of the protocol, so data from these patients were compared with those of patients in the ZMapp group who were enrolled at or after the time the REGN-EB3 group was added (the ZMapp subgroup). The primary end point was death at 28 days. RESULTS: A total of 681 patients were enrolled from November 20, 2018, to August 9, 2019, at which time the data and safety monitoring board recommended that patients be assigned only to the MAb114 and REGN-EB3 groups for the remainder of the trial; the recommendation was based on the results of an interim analysis that showed superiority of these groups to ZMapp and remdesivir with respect to mortality. At 28 days, death had occurred in 61 of 174 patients (35.1%) in the MAb114 group, as compared with 84 of 169 (49.7%) in the ZMapp group (P = 0.007), and in 52 of 155 (33.5%) in the REGN-EB3 group, as compared with 79 of 154 (51.3%) in the ZMapp subgroup (P = 0.002). A shorter duration of symptoms before admission and lower baseline values for viral load and for serum creatinine and aminotransferase levels each correlated with improved survival. Four serious adverse events were judged to be potentially related to the trial drugs. CONCLUSIONS: Both MAb114 and REGN-EB3 were superior to ZMapp in reducing mortality from EVD. Scientifically and ethically sound clinical research can be conducted during disease outbreaks and can help inform the outbreak response. (Funded by the National Institute of Allergy and Infectious Diseases and others; PALM ClinicalTrials.gov number, NCT03719586.).
Subject(s)
Alanine/analogs & derivatives , Antibodies, Monoclonal/therapeutic use , Antiviral Agents/therapeutic use , Hemorrhagic Fever, Ebola/drug therapy , Ribonucleotides/therapeutic use , Adenosine Monophosphate/analogs & derivatives , Adolescent , Adult , Alanine/adverse effects , Alanine/therapeutic use , Antibodies, Monoclonal/adverse effects , Antiviral Agents/adverse effects , Child , Child, Preschool , Democratic Republic of the Congo/epidemiology , Disease Outbreaks , Ebolavirus/genetics , Female , Hemorrhagic Fever, Ebola/mortality , Humans , Infant , Infant, Newborn , Infusions, Intravenous , Male , RNA, Viral/blood , Ribonucleotides/adverse effects , Single-Blind Method , Young AdultABSTRACT
Bacterial vaginosis (BV), a condition in which the vaginal microbiota consists of community of obligate and facultative anaerobes rather than dominated by a single species of Lactobacillus, affects ~30% of women in the US. Women with BV are at 60% increased risk for HIV acquisition and are 3-times more likely to transmit HIV to an uninfected partner. As cervicovaginal mucus (CVM) is the first line of defense against mucosal pathogens and the home of the resident vaginal microbiota, we hypothesized the barrier function of CVM to HIV may be diminished in BV. Here, we characterized CVM properties including pH, lactic acid content, and Nugent score to correlate with the microbiota community composition, which was confirmed by 16S rDNA sequencing on a subset of samples. We then quantified the mobility of fluorescently-labeled HIV virions and nanoparticles to characterize the structural and adhesive barrier properties of CVM. Our analyses included women with Nugent scores categorized as intermediate (4-6) and BV (7-10), women that were either symptomatic or asymptomatic, and a small group of women before and after antibiotic treatment for symptomatic BV. Overall, we found that HIV virions had significantly increased mobility in CVM from women with BV compared to CVM from women with Lactobacillus crispatus-dominant microbiota, regardless of whether symptoms were present. We confirmed using nanoparticles and scanning electron microscopy that the impaired barrier function was due to reduced adhesive barrier properties without an obvious degradation of the physical CVM pore structure. We further confirmed a similar increase in HIV mobility in CVM from women with Lactobacillus iners-dominant microbiota, the species most associated with transitions to BV and that persists after antibiotic treatment for BV. Our findings advance the understanding of the protective role of mucus and highlight the interplay between vaginal microbiota and the innate barrier function mucus.
Subject(s)
Cervix Uteri/microbiology , Cervix Uteri/virology , HIV Infections/virology , Vagina/microbiology , Vagina/virology , Vaginosis, Bacterial/microbiology , Adult , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , Coinfection/microbiology , Coinfection/virology , Female , HIV-1/physiology , Humans , Microbiota , Middle Aged , Mucus/microbiology , Mucus/virology , Young AdultABSTRACT
BACKGROUND: MB66 film is a multipurpose prevention technology (MPT) product with monoclonal antibodies (mAbs) against HIV-1 (VRC01-N) and HSV-1 and 2 (HSV8-N). The mAbs were produced by transient expression in Nicotiana benthamiana (N). We conducted a Phase I clinical trial to assess the safety, pharmacokinetics (PK), and ex vivo efficacy of single and repeated doses of MB66 when used intravaginally. METHODS AND FINDINGS: The clinical trial enrolled healthy reproductive-aged, sexually abstinent women. In Segment A, 9 women received a single MB66 film which was inserted into the vaginal posterior fornix by a clinician. In Segment B, 29 women were randomly assigned to MB66 (Active) or Placebo film groups and were instructed to insert 1 film vaginally for 7 consecutive days. Visits and clinical sampling occurred predose and at various time points after single and repeated film doses. The primary endpoint was number of adverse events (AEs) Grade 2 or higher related to product use. Secondary endpoints included film dissolution rate, Nugent score (a Gram stain scoring system to diagnose bacterial vaginosis), vaginal pH, post-use survey results, cytokine concentrations in cervicovaginal lavage (CVL) specimens (assessed by Luminex assay), mAb concentrations in vaginal fluid collected from 4 sites (assessed by ELISA), and HIV and HSV neutralization activity of CVL samples ex vivo (assessed by TZM-bl and plaque reduction assay, respectively). The product was generally safe and well tolerated, with no serious AEs recorded in either segment. The AEs in this study were primarily genitourinary in nature with the most commonly reported AE being asymptomatic microscopic hematuria. There were no differences in vaginal pH or Nugent scores or significant increases in levels of proinflammatory cytokines for up to 7 days after film insertion in either segment or between Active and Placebo groups. Acceptability and willingness to use the product were judged to be high by post-use surveys. Concentrations of VRC01-N and HSV8-N in vaginal secretions were assessed over time to generate pharmacokinetic curves. Antibody levels peaked 1 hour postdosing with Active film (median: 35 µg/mL) and remained significantly elevated at 24 hours post first and seventh film (median: 1.8 µg/mL). Correcting for sample dilution (1:20), VRC01-N concentrations ranged from 36 to 700 µg/mL at the 24-hour time point, greater than 100-fold the IC50 for VRC01 (0.32 µg/mL); HSV8-N concentrations ranged from 80 to 601 µg/mL, well above the IC50 of 0.1 µg/m. CVL samples collected 24 hours after MB66 insertion significantly neutralized both HIV-1 and HSV-2 ex vivo. Study limitations include the small size of the study cohort, and the fact that no samples were collected between 24 hours and 7 days for pharmacokinetic evaluation. CONCLUSIONS: Single and repeated intravaginal applications of MB66 film were safe, well tolerated, and acceptable. Concentrations and ex vivo bioactivity of both mAbs in vaginal secretions were significantly elevated and thus could provide protection for at least 24 hours postdose. However, further research is needed to evaluate the efficacy of MB66 film in women at risk for HIV and HSV infection. Additional antibodies could be added to this platform to provide protection against other sexually transmitted infections (STIs) and contraception. TRIAL REGISTRATION: ClinicalTrials.gov NCT02579083.
Subject(s)
Antibodies, Monoclonal/therapeutic use , HIV Antibodies/therapeutic use , HIV Infections/drug therapy , HIV-1/drug effects , Administration, Intravaginal , Adolescent , Adult , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Broadly Neutralizing Antibodies/metabolism , Broadly Neutralizing Antibodies/therapeutic use , Female , HIV Antibodies/administration & dosage , HIV Antibodies/immunology , HIV-1/immunology , Humans , Male , Middle Aged , Pre-Exposure Prophylaxis/methods , Vagina/virology , Young AdultABSTRACT
Sexually transmitted infections are highly prevalent, and over 40% of pregnancies are unplanned. We are producing new antibody-based multipurpose prevention technology products to address these problems and fill an unmet need in female reproductive health. We used a Nicotiana platform to manufacture monoclonal antibodies against two prevalent sexually transmitted pathogens, HIV-1 and HSV-2, and incorporated them into a vaginal film (MB66) for preclinical and Phase 1 clinical testing. These tests are now complete and indicate that MB66 is effective and safe in women. We are now developing an antisperm monoclonal antibody to add contraceptive efficacy to this product. The antisperm antibody, H6-3C4, originally isolated by Shinzo Isojima from the blood of an infertile woman, recognizes a carbohydrate epitope on CD52g, a glycosylphosphatidylinositol-anchored glycoprotein found in abundance on the surface of human sperm. We engineered the antibody for production in Nicotiana; the new antibody which we call "human contraception antibody," effectively agglutinates sperm at concentrations >10 µg/ml and maintains activity under a variety of physiological conditions. We are currently seeking regulatory approval for a Phase 1 clinical trial, which will include safety and "proof of principle" efficacy endpoints. Concurrently, we are working with new antibody production platforms to bring the costs down, innovative antibody designs that may produce more effective second-generation antibodies, and delivery systems to provide extended protection.
Subject(s)
Antibodies, Monoclonal , Contraception/methods , Reproductive Health , Female , Humans , MaleABSTRACT
BACKGROUND: Lactic acid (protonated lactate) has broad antimicrobial activity. Vaginal lactobacilli produce lactic acid, and are known to confer protection against reproductive tract infections when they are predominant in the vaginal microbiota. Using novel ex vivo methods, we showed that cervicovaginal fluid (CVF) from women with a predominantly lactobacilli-morphotype microbiota contains significantly more lactic acid than previously thought, sufficient to inactivate reproductive tract pathogens. Here, we measured vaginal pH in vivo in 20 women with a predominantly lactobacilli-morphotype (low Nugent score) microbiota. We also investigated the in vitro production of protons (as hydrogen ions) and lactate by vaginal lactobacilli. RESULTS: The average vaginal pH in these women was 3.80 ± 0.20, and the average lactate concentration was 0.79% ± 0.22% w/v, with pH and lactate concentration tightly correlated for each sample. In vitro, lactobacilli cultured from these CVF samples reached an average pH of 3.92 ± 0.22, but the average lactate concentration was only 0.14% ± 0.06% w/v, approximately five-fold less than in the corresponding CVF samples. When the pH of the cultures was raised, lactate and hydrogen ion production resumed, indicating that production of lactate and hydrogen ions by vaginal lactobacilli is limited primarily by their sensitivity to hydrogen ion concentration (low pH) not lactate concentration. CONCLUSIONS: Some vaginal lactobacilli cultures have a lower limiting pH than others, and limiting pHs in vitro showed good correlation with pHs measured in vivo. The limiting pH of the lactobacilli predominant in a woman's vaginal microbiota seems critical in determining the concentration of antimicrobial lactic acid protecting her.
Subject(s)
Lactic Acid/metabolism , Lactobacillus/physiology , Vagina/microbiology , Adult , Female , Humans , Hydrogen-Ion Concentration , Microbiota/physiology , Vagina/chemistry , Young AdultABSTRACT
The broadly neutralizing antibody (bNAb) VRC01, capable of neutralizing 91% of known human immunodeficiency virus type 1 (HIV-1) isolates in vitro, is a promising candidate microbicide for preventing sexual HIV infection when administered topically to the vagina; however, accessibility to antibody-based prophylactic treatment by target populations in sub-Saharan Africa and other underdeveloped regions may be limited by the high cost of conventionally produced antibodies and the limited capacity to manufacture such antibodies. Intravaginal rings of the pod design (pod-IVRs) delivering Nicotiana-manufactured VRC01 (VRC01-N) over a range of release rates have been developed. The pharmacokinetics and preliminary safety of VRC01-N pod-IVRs were evaluated in a rhesus macaque model. The devices sustained VRC01-N release for up to 21 days at controlled rates, with mean steady-state VRC01-N levels in vaginal fluids in the range of 102 to 103 µg g-1 being correlated with in vitro release rates. No adverse safety indications were observed. These findings indicate that pod-IVRs are promising devices for the delivery of the candidate topical microbicide VRC01-N against HIV-1 infection and merit further preclinical evaluation.
Subject(s)
Anti-HIV Agents/therapeutic use , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/therapeutic use , HIV Infections/drug therapy , Administration, Intravaginal , Animals , Anti-HIV Agents/administration & dosage , Antibodies, Neutralizing/administration & dosage , Antibodies, Neutralizing/therapeutic use , Broadly Neutralizing Antibodies , Female , HIV Antibodies , HIV-1/drug effects , HIV-1/pathogenicity , Macaca mulattaABSTRACT
BACKGROUND: Rhesus and cynomologus macaques are valuable animal models for the study of human immunodeficiency virus (HIV) prevention strategies. However, for such studies focused on the vaginal route of infection, differences in vaginal environment may have deterministic impact on the outcome of such prevention, providing the rationale for this study. METHODS: We tested the vaginal environment of rhesus and cynomolgus macaques longitudinally to characterize the normal microflora based on Nugent scores and pH. This evaluation was extended after colonization of the vaginal space with Lactobacilli in an effort to recreate NHP models representing the healthy human vaginal environment. RESULTS AND CONCLUSION: Nugent scores and pH differed significantly between species, although data from both species were suggestive of stable bacterial vaginosis. Colonization with Lactobacilli was successful in both species leading to lower Nugent score and pH, although rhesus macaques appeared better able to sustain Lactobacillus spp over time.
Subject(s)
Lactobacillus/physiology , Macaca fascicularis/microbiology , Macaca mulatta/microbiology , Vagina/microbiology , Animals , Disease Models, Animal , Female , HIV Infections/prevention & control , Humans , Reference ValuesABSTRACT
Small-animal models of lentivirus transmission have repeatedly demonstrated transmission by cell-associated virus via vaginal, rectal, and oral routes. The earliest experiments were in the cat/feline immunodeficiency virus model, followed a decade later by successful vaginal transmission of cell-associated human immunodeficiency virus (HIV) in mice bearing transplanted human immune cells. After early unsuccessful attempts at cell-associated transmission in nonhuman primates, renewed investigation in diverse primate models has now confirmed the findings from the cat and humanized mouse models. Improvements in humanized mouse models have made them the preferred small-animal models to study HIV mucosal transmission. They provide complementary systems to nonhuman primate models to aid in the elucidation of the many remaining questions on the mechanism of and means to prevent both cell-associated and cell-free HIV transmission across mucosal barriers.
Subject(s)
HIV Infections/transmission , HIV-1/physiology , Lentivirus Infections/transmission , Lentivirus/physiology , Animals , Cats/virology , Disease Models, Animal , HIV Infections/prevention & control , Humans , Leukocytes/virology , Macaca mulatta/virology , Mice/virologyABSTRACT
Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in infants, the immunocompromised, and the elderly. RSV infects the airway epithelium via the apical membrane and almost exclusively sheds progeny virions back into the airway mucus (AM), making RSV difficult to target by systemically administered therapies. An inhalable "muco-trapping" variant of motavizumab (Mota-MT), a potent neutralizing mAb against RSV F is engineered. Mota-MT traps RSV in AM via polyvalent Fc-mucin bonds, reducing the fraction of fast-moving RSV particles in both fresh pediatric and adult AM by ≈20-30-fold in a Fc-glycan dependent manner, and facilitates clearance from the airways of mice within minutes. Intranasal dosing of Mota-MT eliminated viral load in cotton rats within 2 days. Daily nebulized delivery of Mota-MT to RSV-infected neonatal lambs, beginning 3 days after infection when viral load is at its maximum, led to a 10 000-fold and 100 000-fold reduction in viral load in bronchoalveolar lavage and lung tissues relative to placebo control, respectively. Mota-MT-treated lambs exhibited reduced bronchiolitis, neutrophil infiltration, and airway remodeling than lambs receiving placebo or intramuscular palivizumab. The findings underscore inhaled delivery of muco-trapping mAbs as a promising strategy for the treatment of RSV and other acute respiratory infections.
Subject(s)
Antibodies, Monoclonal , Respiratory Syncytial Virus Infections , Humans , Infant , Child , Animals , Sheep , Mice , Aged , Antibodies, Monoclonal/therapeutic use , Respiratory Syncytial Virus Infections/drug therapy , Palivizumab/therapeutic use , Respiratory Syncytial Viruses , LungABSTRACT
OBJECTIVES: When Lactobacillus spp. dominate the vaginal microbiota of women of reproductive age they acidify the vagina to pH <4.0 by producing â¼1% lactic acid in a nearly racemic mixture of d- and l-isomers. We determined the HIV virucidal activity of racemic lactic acid, and its d- and l-isomers, compared with acetic acid and acidity alone (by the addition of HCl). METHODS: HIV-1 and HIV-2 were transiently treated with acids in the absence or presence of human genital secretions at 37°C for different time intervals, then immediately neutralized and residual infectivity determined in the TZM-bl reporter cell line. RESULTS: l-lactic acid at 0.3% (w/w) was 17-fold more potent than d-lactic acid in inactivating HIVBa-L. Complete inactivation of different HIV-1 subtypes and HIV-2 was achieved with ≥0.4% (w/w) l-lactic acid. At a typical vaginal pH of 3.8, l-lactic acid at 1% (w/w) more potently and rapidly inactivated HIVBa-L and HIV-1 transmitter/founder strains compared with 1% (w/w) acetic acid and with acidity alone, all adjusted to pH 3.8. A final concentration of 1% (w/w) l-lactic acid maximally inactivated HIVBa-L in the presence of cervicovaginal secretions and seminal plasma. The anti-HIV activity of l-lactic acid was pH dependent, being abrogated at neutral pH, indicating that its virucidal activity is mediated by protonated lactic acid and not the lactate anion. CONCLUSIONS: l-lactic acid at physiological concentrations demonstrates potent HIV virucidal activity distinct from acidity alone and greater than acetic acid, suggesting a protective role in the sexual transmission of HIV.
Subject(s)
HIV-1/drug effects , HIV-2/drug effects , Lactic Acid/metabolism , Microbial Viability/drug effects , Virus Inactivation , Body Fluids/virology , Female , HIV-1/physiology , HIV-2/physiology , Humans , Lactobacillus/metabolism , Temperature , Vagina/microbiologyABSTRACT
High rates of unintended pregnancies worldwide indicate a need for more accessible and acceptable methods of contraception. We have developed a monoclonal antibody, the Human Contraception Antibody (HCA), for use by women in vaginal films and rings for contraception. The divalent F(ab')2 region of HCA binds to an abundant male reproductive tract-specific antigen, CD52g, and potently agglutinates sperm. Certain other antibody activities mediated by the Fc region such as mucus trapping, complement-dependent cytotoxicity (CDC) and antibody-dependent cellular phagocytosis (ADCP) could have beneficial or negative effects. The purpose of this study was to document HCA Fc effector functions and determine whether an engineered variant of HCA with a modified Fc region, HCA-LALAPG, retains desirable contraceptive activity while minimizing Fc-mediated effects. Fab and Fc functions were compared between HCA and HCA-LALAPG. Fab activity was assessed using sperm agglutination and modified swim-up ("sperm escape") assays. Fc functions were assessed by CDC (sperm immobilization), ADCP, and cervical mucus penetration assays. HCA and HCA-LALAPG showed equivalent activity in assays of Fab function. In the assays of Fc function, HCA supported strong CDC, ADCP, and sperm trapping in cervical mucus whereas HCA-LALAPG demonstrated little to no activity. HCA and the HCA-LALAPG variant were both highly effective in the sperm agglutination assays but differed in Fc mediated functions. Use of the HCA-LALAPG variant for contraception in women could reduce antibody-mediated inflammation and antigen presentation but may have reduced contraceptive efficacy due to much weaker sperm trapping in mucus and complement-dependent sperm immobilization activity.
Subject(s)
Semen , Sperm Agglutination , Pregnancy , Humans , Male , Female , Sperm Agglutination/genetics , Antibodies, Monoclonal , Contraceptive Agents , Contraception , Antibody-Dependent Cell CytotoxicityABSTRACT
BACKGROUND: An objective and accurate method that measures adherence to vaginal microbicide gel regimens during clinical trials could provide more accurate estimates of microbicide efficacy, aid in targeting adherence promotion resources, and enable objective assessment of adherence promotion strategies. METHODS: We evaluated 4 methods to assess whether or not gel applicators had been vaginally inserted. At the study site, 50 women inserted hydroxyethylcellulose universal placebo gel through a polypropylene vaginal applicator and handled, but did not insert a second "sham-inserted" applicator. Applicators were discarded into a container capped with a medical event monitor system (MEMS) that recorded the time and date of opening. Fifteen additional participants did likewise at 2 study site visits, and administered gel on 6 intervening days at home. Applicators were scored as inserted, or not, by direct inspection under ambient light, ultraviolet (UV) light, staining with Alcian blue, and microscopic detection of vaginal cells stained with iodine. RESULTS: Mean sensitivity/specificity of 2 readings each by 3 test readers for UV, Alcian blue, ambient light, and iodine methods were 84/83, 79/83, 76/63, and 65/80%, respectively. Sensitivity of all methods was significantly higher in applicators inserted after one or more prior insertions of gel, with the highest sensitivity (95%) obtained with UV. MEMS caps accurately recorded applicator disposal time. CONCLUSIONS: The modest accuracy of all 4 methods for applicator insertions without prior gel applications may limit their accuracy in monitoring coital regimens. However, for daily dosing regimens, MEMS monitoring and UV inspection should provide a rapid, reliable, and quantitative assessment of adherence.
Subject(s)
Alcian Blue , Anti-Infective Agents/administration & dosage , Coloring Agents , Drug Delivery Systems/instrumentation , Patient Compliance/statistics & numerical data , Sexually Transmitted Diseases, Bacterial/diagnosis , Administration, Intravaginal , Adult , Coitus , Female , Humans , Photoelectron Spectroscopy , Polypropylenes/chemistry , Sensitivity and Specificity , Sexually Transmitted Diseases, Bacterial/drug therapy , Vaginal Creams, Foams, and JelliesABSTRACT
BACKGROUND: Developing effective and safe microbicides requires study procedures (e.g., technology used, abstinence requirements, and product use) that are acceptable to participants. METHODS: Thirty women completed 4 study visits including pelvic examination, colposcopy, optical coherence tomography (OCT), and semistructured, qualitative interviews. Additional requirements included abstinence (for approximately 16 days) and twice daily vaginal product use (for 5.5 days). Interviews were audio-recorded, transcribed, and analyzed using framework analysis. Themes addressing OCT experiences, acceptability of abstinence, and vaginal product use were examined. RESULTS: OCT was viewed favorably as an imaging technology. Some women reported feeling the fiber-optic probe "poking" them and more than one-third spontaneously reported feeling pressure or pinching upon rotation of the speculum in connection with the OCT evaluation. Compliance with vaginal gel use was high, but for many women assigned to use a product containing nonoxynol-9 (vs. placebo), the postproduct use examination was more uncomfortable, relative to the initial examination or 1 week following product discontinuation. Nearly all women experienced product leakage; acceptability of leakage varied. Two women were not abstinent and several more found abstinence challenging. Some women involved their partner in decision making regarding trial enrollment. Strategies to remain abstinent included participating when the partner was away, avoiding early intimacy, and engaging in alternative sexual activities. CONCLUSIONS: Qualitative interviews in early-phase studies provide insights and capture information that would be missed by behavioral inference alone. Understanding participant's experiences is important in order to provide anticipatory guidance and plan future microbicide studies that facilitate adherence with trial requirements.
Subject(s)
Anti-Infective Agents/administration & dosage , Sexual Abstinence/psychology , Tomography, Optical Coherence/methods , Administration, Intravaginal , Adult , Anti-Infective Agents/adverse effects , Female , Humans , Interviews as Topic , Middle Aged , Nonoxynol/administration & dosage , Nonoxynol/adverse effects , Patient Compliance , Patient Satisfaction , Safety , Sexual Behavior , Surface-Active Agents/administration & dosage , Surface-Active Agents/adverse effects , Vaginal Creams, Foams, and Jellies/administration & dosage , Vaginal Creams, Foams, and Jellies/adverse effects , Young AdultABSTRACT
BACKGROUND: Hydrogen peroxide (H2O2) produced by vaginal lactobacilli is generally believed to protect against bacteria associated with bacterial vaginosis (BV), and strains of lactobacilli that can produce H2O2 are being developed as vaginal probiotics. However, evidence that led to this belief was based in part on non-physiological conditions, antioxidant-free aerobic conditions selected to maximize both production and microbicidal activity of H2O2. Here we used conditions more like those in vivo to compare the effects of physiologically plausible concentrations of H2O2 and lactic acid on a broad range of BV-associated bacteria and vaginal lactobacilli. METHODS: Anaerobic cultures of seventeen species of BV-associated bacteria and four species of vaginal lactobacilli were exposed to H2O2, lactic acid, or acetic acid at pH 7.0 and pH 4.5. After two hours, the remaining viable bacteria were enumerated by growth on agar media plates. The effect of vaginal fluid (VF) on the microbicidal activities of H2O2 and lactic acid was also measured. RESULTS: Physiological concentrations of H2O2 (< 100 µM) failed to inactivate any of the BV-associated bacteria tested, even in the presence of human myeloperoxidase (MPO) that increases the microbicidal activity of H2O2. At 10 mM, H2O2 inactivated all four species of vaginal lactobacilli but only one of seventeen species of BV-associated bacteria. Moreover, the addition of just 1% vaginal fluid (VF) blocked the microbicidal activity of 1 M H2O2. In contrast, lactic acid at physiological concentrations (55-111 mM) and pH (4.5) inactivated all the BV-associated bacteria tested, and had no detectable effect on the vaginal lactobacilli. Also, the addition of 10% VF did not block the microbicidal activity of lactic acid. CONCLUSIONS: Under optimal, anaerobic growth conditions, physiological concentrations of lactic acid inactivated BV-associated bacteria without affecting vaginal lactobacilli, whereas physiological concentrations of H2O2 produced no detectable inactivation of either BV-associated bacteria or vaginal lactobacilli. Moreover, at very high concentrations, H2O2 was more toxic to vaginal lactobacilli than to BV-associated bacteria. On the basis of these in vitro observations, we conclude that lactic acid, not H2O2, is likely to suppress BV-associated bacteria in vivo.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Hydrogen Peroxide/pharmacology , Lactic Acid/pharmacology , Vaginal Discharge/microbiology , Vaginosis, Bacterial/microbiology , Adolescent , Adult , Anaerobiosis , Bacteria/genetics , Colony Count, Microbial , Female , Humans , Hydrogen-Ion Concentration , Middle Aged , Young AdultABSTRACT
Many women risk unintended pregnancy because of medical contraindications or dissatisfaction with contraceptive methods, including real and perceived side effects associated with the use of exogenous hormones. We pursued direct vaginal delivery of sperm-binding monoclonal antibodies (mAbs) that can limit progressive sperm motility in the female reproductive tract as a strategy for effective nonhormonal contraception. Here, motivated by the greater agglutination potencies of polyvalent immunoglobulins but the bioprocessing ease and stability of immunoglobulin G (IgG), we engineered a panel of sperm-binding IgGs with 6 to 10 antigen-binding fragments (Fabs), isolated from a healthy immune-infertile woman against a unique surface antigen universally present on human sperm. These highly multivalent IgGs (HM-IgGs) were at least 10- to 16-fold more potent and faster at agglutinating sperm than the parent IgG while preserving the crystallizable fragment (Fc) of IgG that mediates trapping of individual spermatozoa in mucus. The increased potencies translated into effective (>99.9%) reduction of progressively motile sperm in the sheep vagina using as little as 33 µg of the 10-Fab HM-IgG. HM-IgGs were produced at comparable yields and had identical thermal stability to the parent IgG, with greater homogeneity. HM-IgGs represent not only promising biologics for nonhormonal contraception but also a promising platform for engineering potent multivalent mAbs for other biomedical applications.
Subject(s)
Immunoglobulin G , Sperm Motility , Animals , Contraception , Female , Humans , Immunoglobulin Fab Fragments , Male , Pregnancy , Sheep , SpermatozoaABSTRACT
BACKGROUND: Approximately 40% of human pregnancies are unintended, indicating a need for more acceptable effective contraception methods. New antibody production systems make it possible to manufacture reagent-grade human monoclonal antibodies (mAbs) for clinical use. We used the Nicotiana platform to produce a human antisperm mAb and tested its efficacy for on-demand topical contraception. METHODS: Heavy and light chain variable region DNA sequences of a human IgM antisperm antibody derived from an infertile woman were inserted with human IgG1 constant region sequences into an agrobacterium and transfected into Nicotiana benthamiana. The product, an IgG1 mAb ["Human Contraception Antibody" (HCA)], was purified on Protein A columns, and QC was performed using the LabChip GXII Touch protein characterization system and SEC-HPLC. HCA was tested for antigen specificity by immunofluorescence and western blot assays, antisperm activity by sperm agglutination and complement dependent sperm immobilization assays, and safety in a human vaginal tissue (EpiVaginal™) model. FINDINGS: HCA was obtained at concentrations ranging from 0.4 to 4 mg/ml and consisted of > 90% IgG monomers. The mAb specifically reacted with a glycan epitope on CD52g, a glycoprotein produced in the male reproductive tract and found in abundance on sperm. HCA potently agglutinated sperm under a variety of relevant physiological conditions at concentrations ≥ 6.25 µg/ml, and mediated complement-dependent sperm immobilization at concentrations ≥ 1 µg/ml. HCA and its immune complexes did not induce inflammation in EpiVaginal™ tissue. INTERPRETATION: HCA, an IgG1 mAb with potent sperm agglutination and immobilization activity and a good safety profile, is a promising candidate for female contraception. FUNDING: This research was supported by grants R01 HD095630 and P50HD096957 from the National Institutes of Health.
Subject(s)
Antibodies, Monoclonal/immunology , CD52 Antigen/immunology , Contraception, Immunologic/methods , Spermatozoa/immunology , Vaccines, Contraceptive/immunology , Antibody Specificity , Female , Humans , MaleABSTRACT
BACKGROUND: Several active ingredients proposed as vaginal microbicides have been shown paradoxically to increase susceptibility to infection in mouse genital herpes (HSV-2) vaginal susceptibility models and in clinical trials. In addition, "inactive ingredients" (or excipients) used in topical products to formulate and deliver the active ingredient might also cause epithelial toxicities that increase viral susceptibility. However, excipients have not previously been tested in susceptibility models. METHODS: Excipients commonly used in topical products were formulated in a non-toxic vehicle (the "HEC universal placebo"), or other formulations as specified. Twelve hours after exposure to the excipient or a control treatment, mice were challenged with a vaginal dose of HSV-2, and three days later were assessed for infection by vaginal lavage culture to assess susceptibility. RESULTS: The following excipients markedly increased susceptibility to HSV-2 after a single exposure: 5% glycerol monolaurate (GML) formulated in K-Y® Warming Jelly, 5% GML as a colloidal suspension in phosphate buffered saline, K-Y Warming Jelly alone, and both of its humectant/solvent ingredients (neat propylene glycol and neat PEG-8). For excipients formulated in the HEC vehicle, 30% glycerin significantly increased susceptibility, and a trend toward increased HSV-2 susceptibility was observed after 10% glycerin, and 0.1% disodium EDTA, but not after 0.0186% disodium EDTA. The following excipients did not increase susceptibility: 10% propylene glycol, 0.18%, methylparaben plus 0.02% propylparaben, and 1% benzyl alcohol. CONCLUSIONS: As reported with other surfactants, the surfactant/emulsifier GML markedly increased susceptibility to HSV-2. Glycerin at 30% significantly increased susceptibility, and, undiluted propylene glycol and PEG-8 greatly increased susceptibility.
Subject(s)
Anti-Infective Agents/adverse effects , Disease Susceptibility/etiology , Excipients/adverse effects , Herpes Genitalis/transmission , Administration, Intravaginal , Animals , Cellulose/adverse effects , Cellulose/analogs & derivatives , Female , Glycerol/adverse effects , Herpesvirus 2, Human/pathogenicity , Laurates/adverse effects , Mice , Monoglycerides/adverse effects , Phosphates/adverse effects , Polyethylene Glycols/adverse effects , Propylene Glycol/adverse effects , Propylene Glycols/adverse effectsABSTRACT
BACKGROUND: H2O2 produced by vaginal lactobacilli is believed to protect against infection, and H2O2-producing lactobacilli inactivate pathogens in vitro in protein-free salt solution. However, cervicovaginal fluid (CVF) and semen have significant H2O2-blocking activity. METHODS: We measured the H2O2 concentration of CVF and the H2O2-blocking activity of CVF and semen using fluorescence and in vitro bacterial-exposure experiments. RESULTS: The mean H2O2 measured in fully aerobic CVF was 23 +/- 5 microM; however, 50 microM H2O2 in salt solution showed no in vitro inactivation of HSV-2, Neisseria gonorrhoeae, Hemophilus ducreyii, or any of six BV-associated bacteria. CVF reduced 1 mM added H2O2 to an undetectable level, while semen reduced 10 mM added H2O2 to undetectable. Moreover, the addition of just 1% CVF supernatant abolished in vitro pathogen-inactivation by H2O2-producing lactobacilli. CONCLUSIONS: Given the H2O2-blocking activity of CVF and semen, it is implausible that H2O2-production by vaginal lactobacilli is a significant mechanism of protection in vivo.