Publications

Immune system changes with healthy aging lead to chronic systemic inflammation termed inflammaging, contributing to age-related pathologies. Alveolar macrophages (AMs) maintain lung homeostasis and health. The impact of inflammaging on AM populations requires further definition. Herein, we examined the effect of healthy old age on the phenotype and ontogeny of AMs from mice, non-human primates and humans. We identify three AM subpopulations in old age, including a CD11c+CD11b+ population that increases more than 10-fold across mammalian species, leading to significant changes associated with heightened inflammation and immune dysregulation. RNA-seq analysis identifies distinct transcriptional AM subpopulation profiles. Experiments in mice reveal the importance of the alveolar environment in shaping AM phenotype and recruitment in healthy old age. The old age alveolar environment promotes phenotypic reprogramming of tissue-resident AMs (TRAMs) toward a CD11c+CD11b+ state in addition to enhancing CCR2-dependent recruitment of monocyte-derived AMs, which are relatively short-lived and exhibit high turnover due to Fas-mediated apoptosis. These studies provide important insight regarding the impact of the alveolar environment in healthy old age on AM phenotype and function.

Tuberculosis (TB), a disease caused by Mycobacterium tuberculosis, remains one of the major causes of death from infection worldwide, with over a million associated deaths each year. The study of biomarkers for TB is critical for advancing our understanding and management of the disease. Biomarkers, defined as measurable indicators of biological states or conditions, are invaluable for the diagnosis, prognosis and treatment monitoring of TB. Clinical studies have provided critical knowledge on the matter but are also notoriously constrained by economical, ethical and sampling limitations. The use of animal models provides a simpler, more controllable, cost-effective setting with great potential for translation to humans. They also allow the evaluation of biomarkers within the respiratory compartment, when available, which is of particular interest due to the nature of TB pathogenesis. This Review focuses on the current landscape of TB biomarker discovery in several animal models, from invertebrates to large mammals. Here we summarize the basics of host-pathogen immune interaction, describe the main methodological approaches used and highlight the most substantial findings for each animal model studied. Furthermore, we discuss the advantages, challenges and limitations associated with species-specific differences in animal models. We conclude that integrating the data obtained from animal models and human studies is absolutely required to advance the TB field to accelerate the management of this disease.

BACKGROUND: New vaccine approaches are needed against tuberculosis (TB). We sought to optimize mucosal immunogenicity and protective efficacy by modulating the adjuvant component and route of immunization of a next-generation TB vaccine using the recombinant TB vaccine antigen (Ag) ID93.

METHODS: ID93-specific mucosal and systemic immunogenicity and protective efficacy were assessed in the Collaborative Cross 004 mouse strain, a mouse strain susceptible to Mycobacterium tuberculosis (Mtb) infection, as a suitable model of Mtb susceptible populations.

RESULTS: Immunogenicity data from various vaccine candidates were used to select lead vaccine candidates with the most preferred immunostimulatory profiles using a pre-determined desirability index. A liposomal adjuvant system containing synthetic TLR4 and TLR7/8 ligands (GLA-3M-052-LS), administered by a heterologous intramuscular-intranasal regimen, induced an optimal comprehensive immune response profile including high levels of mucosal antibody and Th1 CD4+ T cells in the lungs.

CONCLUSIONS: In BCG-primed mice, immunization with intramuscular followed by intranasal ID93 + GLA-3M-052-LS boosts significantly reduced Mtb burden in the lungs after challenge vs. BCG vaccinated mice alone. Thus, ID93 + GLA-3M-052-LS represents a promising next-generation TB vaccine candidate suitable for testing in additional preclinical models.

BACKGROUND: With >10 million new tuberculosis (TB) cases/year, a limitation to TB control is the lack of simple and accurate tests for TB diagnosis and drug-susceptibility testing (DST) in endemic regions. We evaluated the accuracy of the first-generation, low-complexity phenotypic TB test (1G test), designed for simultaneous Mtb detection and resistance to isoniazid, rifampicin and moxifloxacin, suitable for resource-limited settings.

METHODS: A cross-sectional study was conducted using sputa from 426 possible pulmonary TB subjects from two small Mexican cities bordering Texas. The 1G test was compared against phenotypic TB detection tests in the region [acid fast bacilli smear microscopy and Mycobacteria Growth Indicator Tube (MGIT) culture], and to MGIT-DST for resistance to isoniazid, rifampicin and moxifloxacin.

FINDINGS: The 1G test demonstrated ≥98% sensitivity for Mtb detection, 100% sensitivity and 91% (rifampicin), 94% (isoniazid) and 97% (moxifloxacin) specificity for DST, and less contamination than the MGIT (3.5% vs. 8.1%; p<0.05). The 1G test time to detection (TTD) of Mtb and simultaneous DST was 17-days, while the MGIT-DST required two steps: 7 days for Mtb detection plus 14 more (total 21 days) for DST. Our study site DR-TB prevalence was 14% when testing all consecutively-enrolled participants vs. 6% by passive reporting.

INTERPRETATION: The 1G test is a low-complexity phenotypic TB diagnostic method that is a practical replacement to current culture-based tests. Future studies are warranted to evaluate the implementation of the 1G test in decentralized clinics that lack molecular tools, resources and expertise.

BACKGROUND: Children under the age of 15 represent 3% of the global population living with HIV, 9% of new HIV infections, and 12% of all deaths related to AIDS. This study describes the predictors of HIV among children aged 0-14 years in Nigeria.

METHODS: We analyzed data from a weighted sample of 84 130 443 children aged 0-14 years, collected as part of the 2018 Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS), the largest in the world. Descriptive statistics, chi-square tests, and the Kruskal Wallis Test were employed to assess the differences between HIV-positive children in urban versus rural areas. Adjusted odds ratio (AOR) and 95% Confidence Interval (CI) from logistic regression models were used to delineate predictors of pediatric HIV.

RESULTS: Weighted data on a total of over 84 million children was analyzed, with a slightly higher median age and school enrollment observed among urban residents. HIV prevalence was low overall, at 0.1% in urban areas and 0.2% in rural areas. Among HIV-positive children, maternal awareness of HIV status was a key determinant: children whose mothers were aware of their HIV-positive status had significantly lower likelihood of HIV infection (AOR: 0.02; CI: 0.01-0.06; p <0.001). Conversely, having a living mother (AOR: 6.57; CI: 1.75-24.7; p = 0.005) and younger maternal age were associated with increased likelihood of pediatric HIV. Other sociodemographic and contextual factors, including child's age, sex, residence, school enrollment, and conflict zone status were not significantly associated with pediatric HIV acquisition.

CONCLUSIONS: The findings showed that maternal health significantly influences pediatric HIV outcomes. Children of HIV-positive mothers were less likely to acquire HIV, likely due to ART and PMTCT programs. These findings emphasize the need for strengthened targeted interventions focusing on maternal care, HIV prevention, and healthcare access among vulnerable populations.

OBJECTIVES: HIV remains highly prevalent in sub-Saharan Africa, home to approximately 66 % of all people living with HIV and 85 % of children and adolescents living with HIV globally. The region also experiences the highest levels of armed conflict, resulting in a dual burden of violence and infectious diseases like HIV. Despite these challenges, few studies have explored the impact of war and armed conflict on HIV transmission among adolescents in sub-Saharan Africa. To address this gap in the literature, our study examines HIV risk behaviors among adolescents in both conflict and non-conflict zones of Nigeria.

METHODS: This was a cross-sectional study of adolescents aged 15-19 years, identified through the Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS). We assessed the prevalence of HIV risk behaviors across the entire country, stratified by conflict zone status. Bivariate associations between risk behaviors and conflict status were evaluated using the chi-square test. To identify factors associated with HIV infection among adolescents, we employed survey-weighted logistic regression models, reporting adjusted odds ratios (AOR) and 95 % confidence intervals (CI).

RESULTS: We analyzed 20,518,667 weighted records of adolescents aged 15-19 years, from both conflict (11 %) and non-conflict zones (89 %) of Nigeria. Despite the majority of adolescents residing in non-conflict zones, we found that high-risk behaviors for HIV, such as the non-use of condoms, were more prevalent in conflict zones. However, transactional sex and having two or more sexual partners were significantly higher among adolescents in non-conflict areas. Notably, the risk of HIV infection was over three times higher among adolescents who did not use condoms during sexual intercourse (AOR: 3.22, CI: 1.13, 9.19; p 0.029). Additional risk factors included younger age, educational status, engagement in transactional sex, and having multiple sexual partners.

CONCLUSIONS: This study reports the risk behaviors that contribute to HIV infection among adolescents, particularly within conflict settings. Our findings highlight the link between conflict and heightened HIV risk behaviors among Nigerian adolescents. By identifying these factors and understanding the unique challenges faced by adolescents in conflict zones, more effective, youth-friendly reproductive health programs can be developed for regions impacted by war and conflict.

BACKGROUND: Early diagnosis of TB with drug susceptibility testing (DST) is critical to achieve successful treatment outcomes. We aimed to develop and test a novel colorimetric, 12-well, thin-layer agar-based test to assess its accuracy for TB diagnosis and DST in a clinical setting in Southern Mozambique.

METHODS: Development of the first prototype of the second generation (2G) test in the laboratory setting followed by a cross-sectional diagnostic accuracy study with consecutive recruitment of subjects with microbiologically confirmed TB using GeneXpert MTB/RIF Ultra.

RESULTS: In the laboratory setting, the 2G test showed 100% accuracy in detecting resistance of genotypically characterised drug-resistant Mycobacterium tuberculosis strains. In the clinical setting, the sensitivity of the 2G test to detect M.tb complex versus Xpert and Mycobacteria Growth Indicator Tube (MGIT) culture using fresh sputa was 45.9% and 45.2%, respectively. The 2G test sensitivity versus MGIT decreased to 23.1% when using frozen decontaminated sputum samples.

CONCLUSION: In the clinical setting, the 2G test showed a low sensitivity versus Xpert and MGIT. The 2G test sensitivity was lower when frozen instead of fresh sputa was used. Despite these results, important information was collected to further improve this 2G test prototype and its implementation in resource-constrained settings.

Over the past two decades, betacoronaviruses (β-CoVs) have caused two epidemics and a pandemic and remain a high risk for future outbreaks through zoonotic transmissions, highlighting the need for broad biomedical countermeasures. Here, we describe a convalescent human monoclonal antibody (mAb 1871) that targets the S2 subunit of the coronavirus spike protein, with broad β-CoVs binding and sarbecovirus neutralization. Cryo-electron microscopy analysis revealed that mAb 1871 binds the upstream helix of the S2 subunit, interacting with partially conserved residues, providing a molecular basis for its cross-reactivity. Though less potent than receptor-binding domain-directed antibodies-approximately 500-fold lower neutralization potency than the emergency use authorized receptor-binding domain (RBD)-directed Pemgarda mAb against wild-type SARS-CoV-2-mAb 1871 provides protective efficacy in a mouse model. Notably, Fc effector functions are critical for its in vivo protection. This study further highlights the Fc dependence of S2-directed antibodies for in vivo protection and identifies a conserved epitope in the S2 subunit as a potential target of broad-β-CoVs countermeasures.IMPORTANCEBats and pangolins are natural reservoirs of betacoronaviruses (β-CoVs) and continue to pose a significant risk for future outbreaks through zoonotic transmissions. This highlights the need for effective countermeasures to prevent future pandemics. While neutralizing antibodies targeting the receptor-binding domain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) received emergency use authorization, many have lost efficacy as the virus evolved, and authorizations have been revoked. In contrast to the S1 subunit, the spike protein S2 subunit is more conserved across β-CoVs, making it an attractive target for the development of broadly neutralizing antibodies. Here, we describe a human mAb that targets a conserved epitope in the S2 subunit, demonstrating broad β-CoV binding, sarbecovirus neutralization, and in vivo protection mediated by Fc effector functions in a mouse model. These findings have important implications for pan-β-CoVs therapeutics and vaccine development.

BACKGROUND: The accessible, easy to use and timely, diagnosis of tuberculosis (TB) drug-susceptibility, is often challenging, particularly in resource-constrained settings. We therefore evaluated the phenotypic thin-layer agar based MDR/XDR-TB Colour Test, also known as the "First Generation (1G) Color Plate Test (TB-CX)" performance for detecting resistance of Mycobacterium tuberculosis (Mtb) isolates to selected anti-TB drugs versus other tests routinely used in our setting.

METHODS: A cross-sectional study was conducted on Mtb clinical isolates stored at the Armauer Hansen Research Institute TB laboratory in Addis Ababa, Ethiopia. Drug-susceptibility testing was performed on 78 Mtb isolates for isoniazid, rifampicin, and moxifloxacin using the Colour Test and the Indirect Proportional Method (IPM) "in house" assay. Isoniazid and rifampicin were also evaluated by the Mycobacterial Growth Indicator Tube (MGIT) commercially available assay. Test accuracy was calculated as % agreement with 95% confidence intervals (95%CI).

RESULTS: The median (range) times in days determining Mtb resistance or susceptibility for the Colour Test, IPM and MGIT assays were of 9 (5-18), 15 (13-18) and 19 (14-21) days, respectively. The Colour Test provided results significantly (p < 0.001) more rapidly than the IPM or MGIT assays. The colour test showed a sensitivity and specificity of 91%(95% CI: 87-96) and 87%(95% CI:75-95) for detecting isoniazid resistance,and 93%(95% CI:81-99) and 92%(95% CI:82-97) for detecting rifampicin resistance, respectively, when compared to MGIT DST. For detecting MDR-TB the sensitivity and specificity were 90%(95% CI:76-97) and 96%(95% CI:88-99),respectively. The colour test showed a sensitivity of 97%(95%CI = 87-100) and specificity of 89% (95%CI = 79-96) for detecting isoniazid resistance while for rifampicin resistance,it showed a sensitivity of 82%(95%CI = 64-93)and a specificity of 80%(95% CI = 68-90) rifampicin resistance. Colour Test accuracy compared to IPM to detect isoniazid, rifampicin resistance and MDR-TB was 92% (95%CI = 86-98), 81% (95%CI = 72-90), and 90% (95%CI = 83-96). IPM test accuracy compared to MGIT DST for detecting isoniazid and rifampicin resistance and MDR-TB was 91% (95%CI = 85-97), 83% (95%CI = 75-92), and 85% (95%CI = 77-93), respectively. Moxifloxacin drug-susceptibility testing could not be assessed because only two isolates showed evidence of resistance.

CONCLUSION: The accuracy of Mtb drug-susceptibility testing was similar comparing: Colour Test versus IPM, Colour Test versus MGIT; and comparing IPM versus MGIT. The Colour Test was easy to use and determined drug-susceptibility significantly more rapidly than the IPM and MGIT assays. Thus, implementing the Colour Test in clinical settings could make drug-susceptibility testing more accessible and rapid in high TB burden, and resource-constrained settings, including in Ethiopia.