Intracellular Islatravir-Triphosphate in Dried Blood Spots and Peripheral Blood Mononuclear Cells from Pig-Tailed Macaques.

The purpose of this study was to evaluate the relationship between intracellular islatravir-triphosphate (ISL-TP) in paired peripheral blood mononuclear cells (PBMCs) and dried blood spots (DBS). Three pig-tailed macaques (PMs) were dosed with a single intravaginal extended-release ISL-etonogestrel film for a period of 31 days. After extraction and quantification, repeated measures correlation (rrm) was assessed between log-transformed DBS and PBMC ISL-TP concentrations. Twenty-six paired PBMC/DBS samples were included. Peak ISL-TP concentrations in DBS ranged from 262 to 913 fmol/punches, PBMC Cmax ranged from 427 to 857 fmol/106 cells. Repeated measures correlation yielded an rrm value of 0.96 (95% confidence interval 0.92-0.98; p < .0001). Importantly, ISL-TP was quantifiable in DBS and its pharmacokinetics were similar to PBMC in PMs. Human studies should evaluate DBS applications in clinical pharmacokinetic studies to help define ISL's place in the antiretroviral drug armamentarium.

Evaluation of the Pig-Tailed Macaque (Macaca nemestrina) as a Model of Human Staphylococcus aureus Nasal Carriage.

Staphylococcus aureus nasal carriage is a common condition affecting both healthy and immunocompromised populations and provides a reservoir for dissemination of potentially infectious strains by casual contact. The factors regulating the onset and duration of nasal S. aureus colonization are mostly unknown, and a human-relevant animal model is needed. Here, we screened 17 pig-tailed macaques (Macaca nemestrina) for S. aureus carriage, and 14 of 17 animals tested positive in the nose at one or both screening sessions (8 weeks apart), while the other 3 animals were negative in the nose but positive in the pharynx at least once. As in humans, S. aureus colonization was densest in the nose, and treatment of the nostrils with mupirocin ointment effectively cleared the nostrils and 6 extranasal body sites. Experimental nasal S. aureus colonization was established with 104 CFU/nostril, and both autologous and nonautologous strains survived over 40 days without any apparent adverse effects. A human nasal S. aureus isolate (strain D579, sequence type 398) was carried in 4 of 6 animals for over 3 weeks. Nostrils that did eradicate experimentally applied S. aureus exhibited neutrophilic innate immunity marked by elevated nasal interleukin-1ß (IL-1ß), IL-8, and monocyte chemotactic protein 1 levels and a 10-fold decreased IL-1 receptor antagonist/IL-1ß ratio within 7 days postinoculation, analogous to the human condition. Taken together, pig-tailed macaques represent a physiological model of human S. aureus nasal carriage that may be utilized for testing natural colonization and decolonization mechanisms as well as novel classes of anti-S. aureus therapeutics.

Persistence, immune response, and antigenic variation of Mycoplasma genitalium in an experimentally infected pig-tailed macaque (Macaca nemestrina).

Mycoplasma genitalium is a sexually transmitted pathogen associated with several acute and chronic reproductive tract disease syndromes in men and women. To evaluate the suitability of a pig-tailed macaque model of M. genitalium infection, we inoculated a pilot animal with M. genitalium strain G37 in the uterine cervix and in salpingeal pockets generated by transplanting autologous Fallopian tube tissue subcutaneously. Viable organisms were recovered throughout the 8-week experiment in cervicovaginal specimens and up to 2 weeks postinfection in salpingeal pockets. Humoral and cervicovaginal antibodies reacting to MgpB were induced postinoculation and persisted throughout the infection. The immunodominance of the MgpB adhesin and the accumulation of mgpB sequence diversity previously observed in persistent human infections prompted us to evaluate sequence variation in this animal model. We found that after 8 weeks of infection, sequences within mgpB variable region B were replaced by novel sequences generated by reciprocal recombination with an archived variant sequence located elsewhere on the chromosome. In contrast, mgpB region B of the same inoculum propagated for 8 weeks in vitro remained unchanged. Notably, serum IgG reacted strongly with a recombinant protein spanning MgpB region B of the inoculum, while reactivity to a recombinant protein representing the week 8 variant was reduced, suggesting that antibodies were involved in the clearance of bacteria expressing the original infecting sequence. Together these results suggest that the pig-tailed macaque is a suitable model to study M. genitalium pathogenesis, antibody-mediated selection of antigenic variants in vivo, and immune escape.

Incorporation of the HIV-1 microbicide cyanovirin-N in a food product.

An urgent need exists for HIV-1 microbicides. Here, we describe the in vivo testing of lactic acid bacteria bioengineered to secrete cyanovirin-N. We fed pigtail macaques a yogurt formulation that used bioengineered strains as a starter culture. Cyanovirin-N expression could be detected in the rectal vault during and immediately after feeding. Ex vivo viral challenge of rectal tissue biopsies revealed that peak viral burden was significantly lower in tissue obtained from experimental animals compared with control animals. Formulation of candidate compounds in lactic acid bacteria and their oral administration seems to be a feasible strategy for mucosal delivery of microbicides.

The formulated microbicide RC-101 was safe and antivirally active following intravaginal application in pigtailed macaques.

BACKGROUND: RC-101 is a congener of the antiretroviral peptide retrocyclin, which we and others have reported is active against clinical HIV-1 isolates from all major clades, does not hemagglutinate, and is non-toxic and non-inflammatory in cervicovaginal cell culture. Herein, film-formulated RC-101 was assessed for its antiviral activity in vitro, safety in vivo, retention in the cervix and vagina, and ability to remain active against HIV-1 and SHIV after intravaginal application in macaques. METHODOLOGY/PRINCIPAL FINDINGS: RC-101 was formulated as a quick-dissolving film (2000 µg/film), retained complete activity in vitro as compared to unformulated peptide, and was applied intravaginally in six pigtailed macaques daily for four days. At one and four days following the final application, the presence of RC-101 was assessed in peripheral blood, cervicovaginal lavage, cytobrushed cervicovaginal cells, and biopsied cervical and vaginal tissues by quantitative western blots. One day following the last film application, cervical biopsies from RC-101-exposed and placebo-controlled macaques were collected and were subjected to challenge with RT-SHIV in an ex vivo organ culture model. RC-101 peptide was detected primarily in the cytobrush and biopsied cervical and vaginal tissues, with little to no peptide detected in lavage samples, suggesting that the peptide was associated with the cervicovaginal epithelia. RC-101 remained in the tissues and cytobrush samples up to four days post-application, yet was not detected in any sera or plasma samples. RC-101, extracted from cytobrushes obtained one day post-application, remained active against HIV-1 BaL. Importantly, cervical biopsies from RC-101-treated animals reduced RT-SHIV replication in ex vivo organ culture as compared to placebo-treated animals. CONCLUSIONS/SIGNIFICANCE: Formulated RC-101 was stable in vivo and was retained in the mucosa. The presence of antivirally active RC-101 after five days in vivo suggests that RC-101 would be an important molecule to develop further as a topical microbicide to prevent HIV-1 transmission.

A summary of preclinical topical microbicide vaginal safety and chlamydial efficacy evaluations in a pigtailed macaque model.

BACKGROUND: The development of topical microbicides represents a new and exciting field in the prevention of sexually transmitted diseases, and it is especially important that candidate products undergo rigorous preclinical safety and efficacy testing before advancing to clinical trials. METHODS: We have developed a standardized protocol for preclinical vaginal safety and efficacy assessment of topical microbicide candidates in a nonhuman primate model. Over 7 years of funding under an NIH contract, we evaluated a total of 28 test compounds for vaginal safety (via colposcopy, vaginal pH, and microflora) and 9 compounds for efficacy against cervical chlamydial infection. In this article, we describe our methods in detail and summarize our results, particularly noting the ability of our model to distinguish products with deleterious effects on the cervicovaginal environment. We also outline the specific criteria used to determine which products should move into efficacy trials and which should be recommended for reformulation to the manufacturer. RESULTS: Overall, we noted acceptable safety profiles for 24 of 28 candidate products. Common findings included a transient decrease in vaginal pH, petechiae, and mild erythema. Four products were associated with significant adverse colposcopic findings including blisters, epithelial abrasions, and friability; all 4 products were successfully reformulated and showed acceptable safety profiles at lower concentrations. No products showed complete protection against cervical chlamydial infection. CONCLUSIONS: The macaque preclinical safety and efficacy model is critical to maintaining the pace of topical microbicide development, which could ultimately offer a significant opportunity for intervention in the global HIV/AIDS epidemic.

Lactobacillus crispatus capsules: single-use safety study in the Macaca nemestrina model.

BACKGROUND: Lactobacillus crispatus is a part of the normal vaginal microflora of humans. GOAL: The goal of this study was to assess whether a capsule containing an H2O2-producing strain of L crispatus (CTV-05) would alter the vaginal microflora and/or epithelial tissues when applied intravaginally in the pig-tailed macaque model. STUDY DESIGN: Ten sexually mature female Macaca nemestrina were assessed at baseline for quantitative vaginal microbiology and vaginal pH and with colposcopy. One capsule containing 108 colony forming units of desiccated L crispatus CTV-05 was inserted into the vaginal fornix of each animal. Vaginal assessments were repeated on days 1 and 2 after capsule insertion. The L crispatus CTV-05 strain was identified with use of a DNA fingerprinting method. RESULTS: Before product use, four of 10 animals had detectable levels of H2O2-producing lactobacilli. L crispatus CTV-05 was detected in 1 of 10 animals on day 1 and in 3 of 10 animals on day 2 following insertion of the capsule. There were no tissue changes observed by colposcopy. Vaginal pH decreased in two animals colonized by CTV-05, from 7.0 at baseline to 4.5+/-0.5 on days 1 and 2 after product use. CONCLUSIONS: A single intravaginal application of capsules containing 108 L crispatus CTV-05 resulted in vaginal colonization in three of 10 animals 2 days after use. The absence of colposcopic changes in the vagina/cervical tissues indicates that L crispatus capsules are well tolerated.

Rectal applications of nonoxynol-9 cause tissue disruption in a monkey model.

BACKGROUND: Efforts to develop topical microbicide products have all but ignored evaluation for rectal use. GOAL: The goal of this study was to assess the effects of multiple rectal applications of Conceptrol (containing 4% nonoxynol-9) on flora and mucosal tissues in the pig-tailed macaque model. STUDY DESIGN: Monkeys (8 per group) received daily rectal applications of Conceptrol, placebo gel, or no product, for 3 days. At each visit, a preapplication rectal lavage specimen and swab specimen for microbiology and pH determination were collected. Conceptrol or placebo gel (2.5 ml) was then administered intrarectally. Fifteen minutes after application, samples were again collected. RESULTS: Gross observation of rectal lavage indicated sheets of epithelium 15 minutes after application of the nonoxynol-9 product. Histopathology of these samples revealed epithelial sheets with stroma attached. The presence of H(2)O(2)-producing lactobacilli remained relatively constant, whereas that of H(2)O(2)-producing viridans streptococci diminished in all nonoxynol-9-exposed animals in which these organisms were detected at baseline. CONCLUSIONS: Repeated applications of nonoxynol-9 disrupts the rectal mucosa of the pig-tailed macaque. The disruption of these tissues could have serious implications for an increase in likelihood of acquisition of sexually transmitted infection/HIV in humans.