The Nipah virus is a zoonotic pathogen causing encephalitis and acute respiratory illness in humans with very high fatality rates. Here we report a novel messenger RNA vaccine that directly encodes for a nanoparticle displaying 60 head domains of the Nipah virus G (NiV G) glycoprotein that acts as a highly effective antigen. A vaccine encoding for the NiV G nanoparticle elicits high antibody titers against NiV G and a robust neutralizing antibody response with a pseudotyped Nipah virus system. We ultimately find that the proposed mRNA NiV G nanoparticle (mRNA NiV G-NP) provides a flexible platform for the development of vaccines that will likely be of great value in combatting future Nipah virus outbreaks.

BACKGROUND: HIV-uninfected persons being evaluated for sexually transmitted infections (STIs) may be good HIV pre-exposure prophylaxis (PrEP) candidates. We measured PrEP use in a sentinel STI patient population. DESIGN: Cross-sectional study, New York City Sexual Health Clinics (January-June 2019). METHODS: Remnant serum samples from 644 HIV-uninfected men-who-have-sex-with-men (MSM) and 97 women diagnosed with chlamydia (CT), gonorrhea (GC) and/or early syphilis (ES) were assayed for tenofovir and emtricitabine levels using a validated liquid chromatography-mass spectrometry assay. Using paired test results and medical records, we assessed 1) prevalence and 2) correlates of PrEP use on the day of STI diagnosis (adjusted prevalence ratios [aPR]). RESULTS: PrEP use among 741 patients was 32.7% (95% CI, 29.3%-36.0%); 37.3% for MSM and 2.1% for women. PrEP use was high among White MSM (46.8%) and lowest among women. Among MSM with rectal CT/GC or ES, PrEP use was associated with age [aPR=1.7 (95% CI, 1.2-2.4) for ages 25-34 and aPR=2.0 (1.4-2.9) for ages 35-44, vs. 15-24 years]; number recent sex partners [aPR=1.4 (1.0-2.0) for 3-5 partners, aPR=2.1 (1.5-3.0) for 6-10 partners, aPR=2.2 (1.6-3.1) for >10 partners, vs. <2 partners]; having sex/needle-sharing partners with HIV [aPR=1.4 (1.1-1.7)]; and inconsistent condom use [aPR=3.3 (1.8-6.1)]. Race/ethnicity, past-year STI diagnosis, and post-exposure prophylaxis use were not associated. CONCLUSIONS: One in 3 people with newly diagnosed STIs had detectable serum PrEP, and PrEP use was exceedingly rare among women. Routinely collected remnant samples can be used to measure PrEP use in populations at high risk for HIV acquisition.

BACKGROUND: Intravaginal rings (IVR) for HIV prevention will likely be used by women on depot medroxyprogesterone acetate (DMPA) hormonal contraception. We used pigtailed macaques to evaluate the effects of DMPA on tenofovir disoproxil fumarate (TDF) IVR pharmacokinetics and viral shedding. METHODS: Mucosal tenofovir (TFV) levels were compared in SHIVSF162p3 -negative DMPA-treated (n=4) and normally cycling (n=6) macaques receiving TDF IVRs. Plasma viremia and vaginal shedding were determined in groups of SHIVSF162p3 -positive DMPA-treated (n=6) and normally cycling (n=5) macaques. RESULTS: Similar median vaginal fluid TFV concentrations were observed in the DMPA-treated and cycling macaques over 4 weeks (1.2x105 and 1.1.x105 ng/mL, respectively). Median plasma viremia and vaginal shedding AUC of the DMPA-treated (2.73x107 and 8.15x104 copies/mL, respectively) and cycling macaques (3.98x107 and 1.47x103 copies/mL, respectively) were statistically similar. CONCLUSIONS: DMPA does not affect TDF IVR pharmacokinetics or SHIV shedding.

BACKGROUNDS AND METHODS: A reservoir intravaginal ring (IVR) eluting tenofovir disoproxil fumarate (TDF) was evaluated for 6 months of continuous use in normally cycling female pigtailed macaques with monthly IVR exchanges to define pharmacokinetics and safety. RESULTS AND CONCLUSIONS: Tenofovir levels in vaginal secretions and tissue remained consistent for 6 months with no adverse safety concerns.

Preclinical HIV prevention models use either a single high-dose viral challenge in depot medroxyprogesterone acetate (DMPA)-treated macaques or repeated viral challenges in cycling macaques. We tested the efficacy of an intravaginal tenofovir disoproxil fumarate (TDF) ring in a model combining repeated 30 mg injections of DMPA every 6 weeks with vaginal viral challenges weekly for 12 weeks. Twelve macaques were randomized to TDF or placebo rings. All placebo macaques became infected after a median of 2 exposures, whereas only one TDF macaque became infected at the eighth exposure (p=0.0012). The TDF ring provides durable protection in a stringent challenge model.

BACKGROUND: The limited success of recent HIV topical pre-exposure prophylaxis clinical trials highlights the need for more predictive models of drug efficacy that better simulate what may happen during sexual exposure. To address this gap, we developed complementary in vitro models to evaluate the ability of drugs to retain anti-HIV activity if cells were washed with seminal plasma (simulating what may happen following exposure to ejaculate), and to protect drug-naive T cells (representing newly recruited immune cells) co-cultured with explants that had been pretreated with drug. We focused on tenofovir disoproxil fumarate (TDF), the non-nucleoside reverse transcriptase inhibitors dapivirine (DPV) and IQP-0528, and the entry inhibitors maraviroc (MVC) and the D-peptide chol-PIE-12 trimer (PIE12). Studies were extended to macaques and the ability of cervical biopsies obtained from animals treated with an intravaginal ring formulation of IQP-0528 to protect ex vivo co-cultured T cells was determined. The antiviral activity of cervicovaginal lavage samples against a primary Clade C isolate was also measured and correlated with drug levels. RESULTS: Cells exposed to TDF were equally protected from HIV whether or not the drug-treated cells were washed with medium or seminal plasma prior to challenge. In contrast, several-fold higher concentrations of NNRTIs and entry inhibitors were needed to attain similar levels of HIV inhibition following a wash with seminal plasma. Conversely, the NNRTIs and PIE12, but not TDF or MVC, were effectively transferred from ex vivo treated explants and protected co-cultured T cells. Biopsies obtained from IQP-0528 ring-treated macaques also protected co-cultured T cells with viral inhibition ranging from 42-72%. Antiviral activity correlated with the concentration of drug recovered. Combinations of TDF with IQP-0528 protected in both in vitro models. CONCLUSIONS: Together, these models suggest that intracellularly retained drugs such as TDF may protect resident immune cells following coitus but sustained delivery may be required to protect immune cells subsequently recruited into the genital tract. Sustained delivery may also be critical for NNRTIs, which are rapidly transported out of cells and could be lost following sexual intercourse. An ideal approach may be a combination of drugs with complementary bioavailability profiles formulated for sustained delivery.

Topical preexposure prophylaxis interrupts HIV transmission at the site of mucosal exposure. Intermittently dosed vaginal gels containing the HIV-1 reverse transcriptase inhibitor tenofovir protected pigtailed macaques depending on the timing of viral challenge relative to gel application. However, modest or no protection was observed in clinical trials. Intravaginal rings (IVRs) may improve efficacy by providing long-term sustained drug delivery leading to constant mucosal antiretroviral concentrations and enhancing adherence. Although a few IVRs have entered the clinical pipeline, 100% efficacy in a repeated macaque vaginal challenge model has not been achieved. Here we describe a reservoir IVR technology that delivers the tenofovir prodrug tenofovir disoproxil fumarate (TDF) continuously over 28 d. With four monthly ring changes in this repeated challenge model, TDF IVRs generated reproducible and protective drug levels. All TDF IVR-treated macaques (n = 6) remained seronegative and simian-HIV RNA negative after 16 weekly vaginal exposures to 50 tissue culture infectious dose SHIV162p3. In contrast, 11/12 control macaques became infected, with a median of four exposures assuming an eclipse of 7 d from infection to virus RNA detection. Protection was associated with tenofovir levels in vaginal fluid [mean 1.8 x 10(5) ng/mL (range 1.1 x 10(4) to 6.6 x 10(5) ng/mL)] and ex vivo antiviral activity of cervicovaginal lavage samples. These observations support further advancement of TDF IVRs as well as the concept that extended duration drug delivery devices delivering topical antiretrovirals could be effective tools in preventing the sexual transmission of HIV in humans.

CMI responses, combined with quantification of CMV DNA (DNAemia), may identify transplantation recipients at risk for invasive disease. PBMC were collected in pediatric transplantation candidates at one, three, and six months post-transplant in 10 subjects (six renal, three cardiac, one stem cell) and at single time points in eight HC and 14 children greater than one yr post-transplant (LTTx). Cells were stimulated with anti-CD3mAb or CMV pp65 peptide pools and responses assessed by IFNG enzyme-linked immunosorbent spot assay and cytokine secretion. IFNG responses to anti-CD3mAb were significantly lower pretransplant relative to HC and were further decreased at one and three months post-transplant, but recovered to levels comparable to HC by six months. Responses to pp65 among CMV-seropositive recipients followed a similar pattern but recovered by three months. CMV-seropositive LTTx and HC showed a Th1 cytokine response to pp65 stimulation. Three LTTx subjects developed CMV DNAemia; two demonstrated decreased responses to anti-CD3mAB (and pp65 in the CMV seropositive subject) at the onset of DNAemia, which recovered as DNAemia resolved. Monitoring CMI in children is feasible and may provide an adjunct biomarker to predict CMV progression and recovery.

Immunodeficient mice bearing components of a human immune system present a novel approach for studying human immune responses. We investigated the number, phenotype, developmental kinetics, and function of developing human immune cells following transfer of CD34(+) hematopoietic stem cell (HSC) preparations originating from second trimester human fetal liver (HFL), umbilical cord blood (UCB), or granulocyte colony-stimulating factor-mobilized adult blood (G-CSF-AB) delivered via intrahepatic injection into sublethally irradiated neonatal NOD-scid/gammac(-/-), Balb/c-Rag1(-/-)gammac(-/-), and C.B-17-scid/bg mice. HFL and UCB HSC provided the greatest number and breadth of developing cells. NOD-scid/gammac(-/-) and Balb/c-Rag1(-/-)gammac(-/-) harbored human B and dendritic cells as well as human platelets in peripheral blood, whereas NOD-scid/gammac(-/-) mice harbored higher levels of human T cells. NOD-scid/gammac(-/-) mice engrafted with HFL CD34(+) HSC demonstrated human immunological competence evidenced by white pulp expansion and increases in total human immunoglobulin following immunization with T-dependent antigens and delayed-type hypersensitivity-infiltrating leukocytes in response to antigenic challenge. In conclusion, we describe an encouraging base system for studying human hematopoietic lineage development and function utilizing human HFL or UCB HSC-engrafted NOD-scid/gammac(-/-) mice that is well suited for future studies toward the development of a fully competent humanized mouse model.