Accelerated Clearance and Degradation of Cell-Free HIV by Neutralizing Antibodies Occurs via FcγRIIb on Liver Sinusoidal Endothelial Cells by Endocytosis.

Neutralizing Abs suppress HIV infection by accelerating viral clearance from blood circulation in addition to neutralization. The elimination mechanism is largely unknown. We determined that human liver sinusoidal endothelial cells (LSEC) express FcγRIIb as the lone Fcγ receptor, and using humanized FcγRIIb mouse, we found that Ab-opsonized HIV pseudoviruses were cleared considerably faster from circulation than HIV by LSEC FcγRIIb. Compared with humanized FcγRIIb-expressing mice, HIV clearance was significantly slower in FcγRIIb knockout mice. Interestingly, a pentamix of neutralizing Abs cleared HIV faster compared with hyperimmune anti-HIV Ig (HIVIG), although the HIV Ab/Ag ratio was higher in immune complexes made of HIVIG and HIV than pentamix and HIV. The effector mechanism of LSEC FcγRIIb was identified to be endocytosis. Once endocytosed, both Ab-opsonized HIV pseudoviruses and HIV localized to lysosomes. This suggests that clearance of HIV, endocytosis, and lysosomal trafficking within LSEC occur sequentially and that the clearance rate may influence downstream events. Most importantly, we have identified LSEC FcγRIIb-mediated endocytosis to be the Fc effector mechanism to eliminate cell-free HIV by Abs, which could inform development of HIV vaccine and Ab therapy.

A bioorthogonal chemical reporter for fatty acid synthase-dependent protein acylation.

Mammalian cells acquire fatty acids (FAs) from dietary sources or via de novo palmitate production by fatty acid synthase (FASN). Although most cells express FASN at low levels, it is upregulated in cancers of the breast, prostate, and liver, among others, and is required during the replication of many viruses, such as dengue virus, hepatitis C, HIV-1, hepatitis B, and severe acute respiratory syndrome coronavirus 2, among others. The precise role of FASN in disease pathogenesis is poorly understood, and whether de novo FA synthesis contributes to host or viral protein acylation has been traditionally difficult to study. Here, we describe a cell-permeable and click chemistry-compatible alkynyl acetate analog (alkynyl acetic acid or 5-hexynoic acid [Alk-4]) that functions as a reporter of FASN-dependent protein acylation. In an FASN-dependent manner, Alk-4 selectively labels the cellular protein interferon-induced transmembrane protein 3 at its known palmitoylation sites, a process that is essential for the antiviral activity of the protein, and the HIV-1 matrix protein at its known myristoylation site, a process that is required for membrane targeting and particle assembly. Alk-4 metabolic labeling also enabled biotin-based purification and identification of more than 200 FASN-dependent acylated cellular proteins. Thus, Alk-4 is a useful bioorthogonal tool to selectively probe FASN-mediated protein acylation in normal and diseased states.

Study protocol for reducing disparity in receipt of mother's own milk in very low birth weight infants (ReDiMOM): a randomized trial to improve adherence to sustained maternal breast pump use.

BACKGROUND: Black very low birth weight (VLBW; < 1500 g birth weight) and very preterm (VP, < 32 weeks gestational age, inclusive of extremely preterm, < 28 weeks gestational age) infants are significantly less likely than other VLBW and VP infants to receive mother's own milk (MOM) through to discharge from the neonatal intensive care unit (NICU). The costs associated with adhering to pumping maternal breast milk are borne by mothers and contribute to this disparity. This randomized controlled trial tests the effectiveness and cost-effectiveness of an intervention to offset maternal costs associated with pumping. METHODS: This randomized control trial will enroll 284 mothers and their VP infants to test an intervention (NICU acquires MOM) developed to facilitate maternal adherence to breast pump use by offsetting maternal costs that serve as barriers to sustaining MOM feedings and the receipt of MOM at NICU discharge. Compared to current standard of care (mother provides MOM), the intervention bundle includes three components: a) free hospital-grade electric breast pump, b) pickup of MOM, and c) payment for opportunity costs. The primary outcome is infant receipt of MOM at the time of NICU discharge, and secondary outcomes include infant receipt of any MOM during the NICU hospitalization, duration of MOM feedings (days), and cumulative dose of MOM feedings (total mL/kg of MOM) received by the infant during the NICU hospitalization; maternal duration of MOM pumping (days) and volume of MOM pumped (mLs); and total cost of NICU care. Additionally, we will compare the cost of the NICU acquiring MOM versus NICU acquiring donor human milk if MOM is not available and the cost-effectiveness of the intervention (NICU acquires MOM) versus standard of care (mother provides MOM). DISCUSSION: This trial will determine the effectiveness of an economic intervention that transfers the costs of feeding VLBWand VP infants from mothers to the NICU to address the disparity in the receipt of MOM feedings at NICU discharge by Black infants. The cost-effectiveness analysis will provide data that inform the adoption and scalability of this intervention. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04540575 , registered September 7, 2020.

Interferon-induced transmembrane proteins inhibit cell fusion mediated by trophoblast syncytins.

Type I interferon (IFN) induced by virus infections during pregnancy can cause placental damage, but the mechanisms and identities of IFN-stimulated genes that are involved in this damage remain under investigation. The IFN-induced transmembrane proteins (IFITMs) inhibit virus infections by preventing virus membrane fusion with cells and by inhibiting fusion of infected cells (syncytialization). Fusion of placental trophoblasts via expression of endogenous retroviral fusogens known as syncytins forms the syncytiotrophoblast, a multinucleated cell structure essential for fetal development. We found here that IFN blocks fusion of BeWo human placental trophoblasts. Stably expressed IFITM1, -2, and -3 also blocked fusion of these trophoblasts while making them more resistant to virus infections. Conversely, stable IFITM knockdowns in BeWo trophoblasts increased their spontaneous fusion and allowed fusion in the presence of IFN while also making the cells more susceptible to virus infection. We additionally found that exogenous expression of IFITMs in HEK293T cells blocked fusion with cells expressing syncytin-1 or syncytin-2, confirming the ability of IFITMs to block individual syncytin-mediated fusion. Overall, our data indicate that IFITMs inhibit trophoblast fusion and suggest that there may be a critical balance between these antifusogenic effects and the beneficial antiviral effects of IFITMs in virus infections during pregnancy.

In Vitro Exposure of Leukocytes to HIV Preexposure Prophylaxis Decreases Mitochondrial Function and Alters Gene Expression Profiles.

The use of antiretroviral therapy (ART) as preexposure prophylaxis (PrEP) is an effective strategy for preventing HIV acquisition. The cellular consequences of PrEP exposure, however, have not been sufficiently explored to determine potential effects on health in individuals without HIV. In this study, peripheral blood mononuclear cells (PBMCs) from people without HIV were exposed to tenofovir disoproxil fumarate (TDF) or emtricitabine (FTC) overnight. Mitochondrial mass and function were measured by flow cytometry and an Agilent XFp analyzer. Monocyte-derived macrophages (MDMs) were differentiated in 20% autologous serum for 5 days in the presence or absence of TDF or FTC, and surface markers, lipid uptake, and efferocytosis were measured by flow cytometry. MDM gene expression was measured using transcriptome sequencing (RNA-seq). Plasma lipids were measured using mass spectrometry. PBMCs exposed to TDF or FTC had decreased maximal oxygen consumption rate (OCR) and reduced mitochondrial mass. Exposure to PrEP also increased reactive oxygen species (ROS) production from monocyte subsets. Compared to MDMs cultured in medium alone, cells differentiated in the presence of TDF (829 genes) or FTC (888 genes) had significant changes in gene expression. Further, PrEP-exposed MDMs had decreased mitochondrial mass and displayed increased lipid uptake and reduced efferocytosis. Plasma biomarkers and lipid levels were also altered in vivo in individuals receiving a PrEP regimen. In conclusion, exposure of leukocytes to TDF or FTC resulted in decreased mitochondrial function and altered functional and transcriptional profiles. These findings may have important implications for the metabolic and immunologic consequences of PrEP in populations at risk for HIV acquisition.

Cellular fatty acid synthase is required for late stages of HIV-1 replication.

BACKGROUND: Like all viruses, HIV-1 relies on host systems to replicate. The human purinome consists of approximately two thousand proteins that bind and use purines such as ATP, NADH, and NADPH. By virtue of their purine binding pockets, purinome proteins are highly druggable, and many existing drugs target purine-using enzymes. Leveraging a protein affinity media that uses the purine-binding pocket to capture the entire purinome, we sought to define purine-binding proteins regulated by HIV-1 infection. RESULTS: Using purinome capture media, we observed that HIV-1 infection increases intracellular levels of fatty acid synthase (FASN), a NADPH-using enzyme critical to the synthesis of de novo fatty acids. siRNA mediated knockdown of FASN reduced HIV-1 particle production by 80%, and treatment of tissue culture cells or primary PBMCs with Fasnall, a newly described selective FASN inhibitor, reduced HIV-1 virion production by 90% (EC50 = 213 nM). Despite the requirement of FASN for nascent virion production, FASN activity was not required for intracellular Gag protein production, indicating that FASN dependent de novo fatty acid biosynthesis contributes to a late step of HIV-1 replication. CONCLUSIONS: Here we show that HIV-1 replication both increases FASN levels and requires host FASN activity. We also report that Fasnall, a novel FASN inhibitor that demonstrates anti-tumor activity in vivo, is a potent and efficacious antiviral, blocking HIV-1 replication in both tissue culture and primary cell models of HIV-1 replication. In adults, most fatty acids are obtained exogenously from the diet, thus making FASN a plausible candidate for pharmacological intervention. In conclusion, we hypothesize that FASN is a novel host dependency factor and that inhibition of FASN activity has the potential to be exploited as an antiretroviral strategy.

High levels of self-reported prescription opioid use by HIV-positive individuals.

Prescription medication use (other than antiretroviral therapy (ART)) is highly prevalent among people living with HIV. Prescription medications may be used medically or non-medically: non-medical use includes using more medication than prescribed, using medication prescribed to someone else, or using medication for a purpose other than its prescribed use. During 12 weeks in 2014-2015, we characterized medical and non-medical prescription medication use among HIV-positive patients attending an academic medical center (n = 149) and a community clinic (n = 105). Separately for the past year and the past month, these 254 participants self-reported their use of prescription opioids, sedatives, stimulants, anti-anxiety medications, antipsychotic medications, and erectile dysfunction medications. Respondents were largely male (91%), aged 40 or older (61%), identified as gay or bisexual (79%), and were men who have sex with men (85%). ART use was nearly universal (95%). Nearly half (43%) of participants reported medical use of prescription opioids; 11% of the opioid use was reported as non-medical use. Anti-anxiety medication use was also frequent, and differed by site: 41% of community-clinic responders reported medical use of anti-anxiety medications compared to 23% of hospital clinic respondents who reported medical use. Prescription sedative use was also approximately twice as high among community-clinic participants, with medical use reported by 43% of respondents and non-medical use by 12%; in comparison, at the hospital clinic, sedative use was reported by 18% (medical) and 7% (non-medical) of participants. Stimulant use was rare in both sites. No demographic characteristic was significantly associated with medical or non-medical use of any prescription medication. The current focus of many studies on only non-medical prescription medication use not only underestimates the widespread exposure of HIV-positive individuals to these drugs, but may also underestimate potential adverse effects of prescription medications in this population.

Inhibition of Salmonella enterica biofilm formation using small-molecule adenosine mimetics.

Biofilms have been widely implicated in chronic infections and environmental persistence of Salmonella enterica, facilitating enhanced colonization of surfaces and increasing the ability of the bacteria to be transmitted to new hosts. Salmonella enterica serovar Typhi biofilm formation on gallstones from humans and mice enhances gallbladder colonization and bacterial shedding, while Salmonella enterica serovar Typhimurium biofilms facilitate long-term persistence in a number of environments important to food, medical, and farming industries. Salmonella regulates expression of many virulence- and biofilm-related processes using kinase-driven pathways. Kinases play pivotal roles in phosphorylation and energy transfer in cellular processes and possess an ATP-binding pocket required for their functions. Many other cellular proteins also require ATP for their activity. Here we test the hypothesis that pharmacological interference with ATP-requiring enzymes utilizing adenosine mimetic compounds would decrease or inhibit bacterial biofilm formation. Through the screening of a 3,000-member ATP mimetic library, we identified a single compound (compound 7955004) capable of significantly reducing biofilm formation by S. Typhimurium and S. Typhi. The compound was not bactericidal or bacteriostatic toward S. Typhimurium or cytotoxic to mammalian cells. An ATP-Sepharose affinity matrix technique was used to discover potential protein-binding targets of the compound and identified GroEL and DeoD. Compound 7955004 was screened against other known biofilm-forming bacterial species and was found to potently inhibit biofilms of Acinetobacter baumannii as well. The identification of a lead compound with biofilm-inhibiting capabilities toward Salmonella provides a potential new avenue of therapeutic intervention against Salmonella biofilm formation, with applicability to biofilms of other bacterial pathogens.

Expression of flotillins in the human placenta: potential implications for placental transcytosis.

A proteomics survey of human placental syncytiotrophoblast (ST) apical plasma membranes revealed peptides corresponding to flotillin-1 (FLOT1) and flotillin-2 (FLOT2). The flotillins belong to a class of lipid microdomain-associated integral membrane proteins that have been implicated in clathrin- and caveolar-independent endocytosis. In the present study, we characterized the expression of the flotillin proteins within the human placenta. FLOT1 and FLOT2 were coexpressed in placental lysates and BeWo human trophoblast cells. Immunofluorescence microscopy of first-trimester and term placentas revealed that both proteins were more prominent in villous endothelial cells and cytotrophoblasts (CTs) than the ST. Correspondingly, forskolin-induced fusion in BeWo cells resulted in a decrease in FLOT1 and FLOT2, suggesting that flotillin protein expression is reduced following trophoblast syncytialization. The flotillin proteins co-localized with a marker of fluid-phase pinocytosis, and knockdown of FLOT1 and/or FLOT2 expression resulted in decreased endocytosis of cholera toxin B subunit. We conclude that FLOT1 and FLOT2 are abundantly coexpressed in term villous placental CTs and endothelial cells, and in comparison, expression of these proteins in the ST is reduced. These findings suggest that flotillin-dependent endocytosis is unlikely to be a major pathway in the ST, but may be important in the CT and endothelium.

The genetic bottleneck in vertical transmission of subtype C HIV-1 is not driven by selection of especially neutralization-resistant virus from the maternal viral population.

Subtype C human immunodeficiency virus type 1 (HIV-1C) continues to cause the majority of new cases of mother-to-child transmission (MTCT), and yet there are limited data on HIV-1C transmission. We amplified env from plasma RNA for 19 HIV-1C MTCT pairs, 10 transmitting in utero (IU) and 9 transmitting intrapartum (IP). There was a strong genetic bottleneck between all mother-infant pairs, with a majority of transmission events involving the transmission of a single virus. env genes of viruses transmitted to infants IP, but not IU, encoded Env proteins that were shorter and had fewer putative N-linked glycosylation sites in the V1-V5 region than matched maternal sequences. Viruses pseudotyped with env clones representative of each maternal and infant population were tested for neutralization sensitivity. The 50% inhibitory concentration of autologous serum was similar against both transmitted (infant) and nontransmitted (maternal) viruses in a paired analysis. Mother and infant Env proteins were also similar in sensitivity to soluble CD4, to a panel of monoclonal antibodies, and to heterologous HIV-1C sera. In addition, there was no difference in the breadth or potency of neutralizing antibodies between sera from 50 nontransmitting and 23 IU and 23 IP transmitting HIV-1C-infected women against four Env proteins from heterologous viruses. Thus, while a strong genetic bottleneck was detected during MCTC, with viruses of shorter and fewer glycosylation sites in env present in IP transmission, our data do not support this bottleneck being driven by selective resistance to antibodies.

Different regions of HIV-1 subtype C env are associated with placental localization and in utero mother-to-child transmission.

HIV infections are initiated by a limited number of variants that diverge into a diverse quasispecies swarm. During in utero mother-to-child transmission (IU MTCT), transmitted viral variants must pass through multiple unique environments, and our previously published data suggest a nonstochastic model of transmission. As an alternative to a stochastic model of viral transmission, we hypothesize that viral selection in the placental environment influences the character of the viral quasispecies when HIV-1 is transmitted in utero. To test this hypothesis, we used single-template amplification to isolate HIV-1 envelope gene (env) sequences from both peripheral plasma and the placentas of eight nontransmitting (NT) and nine IU-transmitting participants. Statistically significant compartmentalization between peripheral and placental HIV-1 env was detected in one of the eight NT cases and six of the nine IU MTCT cases. In addition, viral sequences isolated from IU MTCT placental tissue showed variation in env V1 loop lengths compared to matched maternal sequences, while NT placental env sequences did not. Finally, comparison of env sequences from NT and IU MTCT participants indicated statistically significant differences in Kyte-Doolittle hydropathy in the signal peptide, C2, V3, and C3 regions. Our working hypothesis is that the hydropathy differences in Env associated with IU MTCT alter viral cellular tropism or affinity, allowing HIV-1 to efficiently infect placentally localized cells.

Expression of membrane Hsp90 is a molecular signature of T cell activation.

Heat shock protein 90 (Hsp90) maintains cellular proteostasis during stress and has been under investigation as a therapeutic target in cancer for over two decades. We and others have identified a membrane expressed form of Hsp90 (mHsp90) that previously appeared to be restricted to rapidly proliferating cells exhibiting a metastatic phenotype. Here, we used HS-131, a fluor-tethered mHsp90 inhibitor, to quantify the effect of T cell activation on the expression of mHsp90 in human and mouse T cells. In cell-based assays, stimulation of human T cells induced a 20-fold increase in mHsp90 expression at the plasma membrane, suggesting trafficking of mHsp90 is regulated by TCR and inflammatory mediated signaling. Following injection of HS-131 in mouse models of human rheumatoid arthritis and inflammatory bowel disease, we detected localization of the probe at sites of active disease, consistent with immune cell invasion. Moreover, despite rapid hepatobiliary clearance, HS-131 demonstrated efficacy in reducing the mean clinical score in the CIA arthritis model. Our results suggest mHsp90 expression on T cells is a molecular marker of T cell activation and potentially a therapeutic target for chronic diseases such as rheumatoid arthritis.

Asymmetric total synthesis of (+)- and (-)-clusianone and (+)- and (-)-clusianone methyl enol ether via ACC alkylation and evaluation of their anti-HIV activity.

The total asymmetric synthesis of (+)- and (-)-clusianone and (+)- and (-)-clusianone methyl enol ether is reported. Asymmetric induction is achieved through the use of ACC alkylation, providing the key intermediates with an er of 99:1. The four synthetic compounds were evaluated for their anti-HIV activity. Both (+)- and (-)-clusianone displayed significant anti-HIV activity.

Norethisterone Enanthate Increases Mouse Susceptibility to Genital Infection with Herpes Simplex Virus Type 2 and HIV Type 1.

Norethisterone enanthate (NET-EN) and depot-medroxyprogesterone acetate (DMPA) are two forms of injectable progestin used for contraception. Whereas clinical research indicates that women using DMPA are more susceptible to HIV and other genital pathogens, causal relationships have not been determined. Providing an underlying mechanism for this connection, however, is recent work that showed DMPA weakens genital mucosal barrier function in mice and humans and respectively promotes susceptibility of wild-type and humanized mice to genital infection with HSV type 2 and HIV type 1. However, analogous effects of NET-EN treatment on antivirus immunity and host susceptibility to genital infection are much less explored. In this study, we show that compared with mice in estrus, treatment of mice with DMPA or NET-EN significantly decreased genital levels of the cell-cell adhesion molecule desmoglein-1 and increased genital mucosal permeability. These effects, however, were more pronounced in DMPA- versus NET-EN-treated mice. Likewise, we detected comparable mortality rates in DMPA- and NET-EN-treated wild-type and humanized mice after intravaginal infection with HSV type 2 or cell-associated HIV type 1, respectively, but NET-EN treatment was associated with slower onset of HSV-induced genital pathology and lower burden of systemic HIV disease. These findings reveal DMPA and NET-EN treatment of mice significantly reduces genital desmoglein-1 levels and increases genital mucosal permeability and susceptibility to genital pathogens while also implying that NET-EN generates less compromise of genital mucosal barrier function than DMPA.

Use of Antiretroviral Therapy During Pregnancy and Adverse Birth Outcomes Among Women Living With HIV-1 in Low- and Middle-Income Countries: A Systematic Review.

BACKGROUND: Worldwide, nearly 18 million women of reproductive age are living with HIV-1. Although increased access to antiretroviral therapy (ART) during pregnancy has significantly reduced HIV-1 mother-to-child transmission (MTCT), a similarly robust reduction in preterm birth (PTB) and low birthweight (LBW) among infants born to women living with HIV has not been observed. This study was designed to identify associations between classes of ART regimens and risk of PTB or LBW. SETTING: Low- and middle-income countries. METHODS: We conducted a systematic review of randomized and observational studies that assessed the effect of ART regimen on the risk of PTB (≤37 completed weeks of gestation) or LBW (<2500 g at birth) among pregnant women in low- and middle-income countries living with HIV-1. We searched Medline, COCHRANE, Web of Science, SCOPUS, and CPCI-S for included studies. RESULTS: When compared to monotherapy, both nonnucleoside reverse transcriptase inhibitor- and protease inhibitor-based regimens had a consistent, harmful association with LBW. There is mixed evidence suggesting both potential harm and potential benefit for most other regimens on risk of LBW and PTB, and the harmful or protective effects of certain regimens varies depending on the drug backbone. CONCLUSIONS: Although the benefits of ART during pregnancy for prevention of MTCT are undisputed, this systematic review indicates that ART regimens vary substantially in their association with LBW and PTB. Although challenging, optimization of ART regimens could simultaneously promote maternal health, prevent MTCT, and also minimize risks of PTB and LBW.

Exogenous oestrogen inhibits genital transmission of cell-associated HIV-1 in DMPA-treated humanized mice.

INTRODUCTION: HIV affects more women than any other life-threatening infectious agent, and most infections are sexually transmitted. HIV must breach the female genital tract mucosal barrier to establish systemic infection, and clinical studies indicate virus more easily evades this barrier in women using depot-medroxyprogesterone acetate (DMPA) and other injectable progestins for contraception. Identifying a potential mechanism for this association, we learned DMPA promotes susceptibility of wild-type mice to genital herpes simplex virus type 2 (HSV-2) infection by reducing genital tissue expression of the cell-cell adhesion molecule desmoglein-1 (DSG-1) and increasing genital mucosal permeability. Conversely, DMPA-mediated increases in genital mucosal permeability and HSV-2 susceptibility were eliminated in mice concomitantly administered exogenous oestrogen (E). To confirm and extend these findings, herein we used humanized mice to define effects of systemic DMPA and intravaginal (ivag) E administration on susceptibility to genital infection with cell-associated HIV-1. METHODS: Effects of DMPA or an intravaginal (ivag) E cream on engraftment of NOD-scid-IL-2Rgcnull  (NSG) mice with human peripheral blood mononuclear cells (hPBMCs) were defined with flow cytometry. Confocal microscopy was used to evaluate effects of DMPA, DMPA and E cream, or DMPA and the pharmacologically active component of the cream on vaginal tissue DSG-1 expression and genital mucosal permeability to low molecular weight (LMW) molecules and hPBMCs. In other studies, hPBMC-engrafted NSG mice (hPBMC-NSG) received DMPA or DMPA and ivag E cream before genital inoculation with 106 HIV-1-infected hPBMCs. Mice were euthanized 10 days after infection, and plasma HIV-1 load quantified by qRT-PCR and splenocytes used to detect HIV-1 p24 antigen via immunohistochemistry and infectious virus via TZM-bl luciferase assay. RESULTS: Whereas hPBMC engraftment was unaffected by DMPA or E treatment, mice administered DMPA and E (cream or the pharmacologically active cream component) displayed greater vaginal tissue expression of DSG-1 protein and decreased vaginal mucosal permeability to LMW molecules and hPBMCs versus DMPA-treated mice. DMPA-treated hPBMC-NSG mice were also uniformly susceptible to genital transmission of cell-associated HIV-1, while no animal concomitantly administered DMPA and E cream acquired systemic HIV-1 infection. CONCLUSION: Exogenous E administration reduces susceptibility of DMPA-treated humanized mice to genital HIV-1 infection.

Low-cost diagnostic test for susceptible and drug-resistant tuberculosis in rural Malawi.

BACKGROUND: Rural settings where molecular tuberculosis diagnostics are not currently available need easy-to-use tests that do not require additional processing or equipment. While acid-fast bacilli (AFB) smear is the most common and often only tuberculosis diagnosis test performed in rural settings, it is labour intensive, has less-than-ideal sensitivity, and cannot assess tuberculosis drug susceptibility patterns. OBJECTIVE: The objective of this study was to determine the feasibility of a multidrug-resistant (MDR) or extensively drug-resistant (XDR)-tuberculosis coloured agar-based culture test (tuberculosis CX-test), which can detect Mycobacterium tuberculosis growth and evaluate for drug susceptibility to isoniazid, rifampicin and a fluoroquinolone (i.e. ciprofloxacin) in approximately 14 days. METHOD: In this study, 101 participants were enrolled who presented to a rural health clinic in central Malawi. They were suspected of having active pulmonary tuberculosis. Participants provided demographic and clinical data and submitted sputum samples for tuberculosis testing using the AFB smear and tuberculosis CX-test. RESULTS: The results showed a high level of concordance between the AFB smear (12 positive) and tuberculosis CX-test (13 positive); only one sample presented discordant results, with the molecular GeneXpert MTB/RIF® test confirming the tuberculosis CX-test results. The average time to a positive tuberculosis CX-test was 10 days. Of the positive samples, the tuberculosis CX-test detected no cases of drug resistance, which was later confirmed by the GeneXpert MTB/RIF®. CONCLUSION: These findings demonstrate that the tuberculosis CX-test could be a reliable low-cost diagnostic method for active pulmonary tuberculosis in high tuberculosis burden rural areas.

Injectable long-acting human immunodeficiency virus antiretroviral prodrugs with improved pharmacokinetic profiles.

While highly active antiretroviral therapy (HAART) has significantly reduced mortality rates in patients with human immunodeficiency virus type 1 (HIV-1), its efficacy may be impeded by emergence of drug resistance caused by lack of patient adherence. A therapeutic strategy that requires infrequent drug administration as a result of sustained release of antiretroviral drugs would put less burden on the patient. Long-acting antiretroviral prodrugs for HIV therapy were synthesized through modification of the active drugs, emtricitabine (FTC) and elvitegravir (EVG), with docosahexaenoic acid (DHA) in one-step, one-pot, high-yielding reactions. The in vitro drug release profiles of these synthetic conjugates demonstrated sustained and controlled release of the active drug over a period of 3-4 weeks attributable to the hydrolysis of the chemical linker in conjunction with the hydrophilicity of the parent drug. Both conjugates exhibited superior antiviral activities in tissue culture models of HIV replication as compared to those of the free drugs, strengthening their role as potent prodrugs for HIV therapy. Pharmacokinetic analysis in CD1 mice further confirmed the long-acting aspect of these conjugates with released drug concentrations in plasma detected at their respective IC90/IC95 values over a period of 2 weeks and discernable amounts of active drug even at 6 weeks. Our findings suggest that the injectable small molecule conjugates could be used as long-acting controlled release of FTC and EVG in attempts to mitigate adherence-related HIV resistance.

Mouse Liver Sinusoidal Endothelium Eliminates HIV-Like Particles from Blood at a Rate of 100 Million per Minute by a Second-Order Kinetic Process.

We crafted human immunodeficiency virus (HIV)-like particles of diameter about 140 nm, which expressed two major HIV-1 proteins, namely, env and gag gene products, and used this reagent to simulate the rate of decay of HIV from the blood stream of BALB/c male mice. We found that most (~90%) of the particles were eliminated (cleared) from the blood by the liver sinusoidal endothelial cells (LSECs), the remainder from Kupffer cells; suggesting that LSECs are the major liver scavengers for HIV clearance from blood. Decay was rapid with kinetics suggesting second order with respect to particles, which infers dimerization of a putative receptor on LSEC. The number of HIV-like particles required for saturating the clearance mechanism was approximated. The capacity for elimination of blood-borne HIV-like particles by the sinusoid was 112 million particles per minute. Assuming that the sinusoid endothelial cells were about the size of glass-adherent macrophages, then elimination capacity was more than 540 particles per hour per endothelial cell.

Maternal syphilis infection is associated with increased risk of mother-to-child transmission of HIV in Malawi.

OBJECTIVE: To determine the association between maternal syphilis and HIV mother-to-child transmission (MTCT). DESIGN: Prospective cohort study. METHODS: Pregnant women admitted at Queen Elizabeth Central Hospital (Malawi) in late third trimester were screened for HIV (by HIV rapid tests) and syphilis (by rapid plasma regain test and Treponema pallidum hemagglutination assay). HIV-infected women and their infants received nevirapine, according to the HIVNET 012 protocol. They were followed up at 6 and 12 weeks postpartum. Infant HIV infection was diagnosed by DNA PCR. FINDINGS: Of the 1155 HIV-infected women enrolled, 1147 had syphilis test results, of whom 92 (8.0%) were infected. Only 751 HIV-positive women delivered live singleton infants who were tested for HIV at birth. Of these, 65 (8.7%) were HIV-infected, suggesting in utero (IU) HIV MTCT. Of the 686 infants who were HIV-negative at birth, 507 were successfully followed up. Of these, 89 (17.6%) became HIV-infected, suggesting intrapartum/postpartum (IP/PP) HIV MTCT. Maternal syphilis was associated with IU HIV MTCT, after adjusting for maternal log10 HIV-1 viral load and low birth weight (LBW) [adjusted relative risk (ARR), 2.77; 95% CI, 1.40-5.46]. Furthermore, maternal syphilis was associated with IP/PP HIV MTCT (ARR, 2.74; 95% CI, 1.58-4.74), after adjusting for recent fever, breast infection, LBW and maternal log10 HIV-1 viral load. CONCLUSION: Maternal syphilis is associated with IU and IP/PP HIV MTCT. Screening and early treatment of maternal syphilis during pregnancy may reduce pediatric HIV infections.