Publications by Year: 2026

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.