One health systems strengthening in countries: Tripartite tools and approaches at the human-animal-environment interface.

Unexpected pathogen transmission between animals, humans and their shared environments can impact all aspects of society. The Tripartite organisations-the Food and Agriculture Organization of the United Nations (FAO), the World Health Organization (WHO), and the World Organisation for Animal Health (WOAH)-have been collaborating for over two decades. The inclusion of the United Nations Environment Program (UNEP) with the Tripartite, forming the 'Quadripartite' in 2021, creates a new and important avenue to engage environment sectors in the development of additional tools and resources for One Health coordination and improved health security globally. Beginning formally in 2010, the Tripartite set out strategic directions for the coordination of global activities to address health risks at the human-animal-environment interface. This paper highlights the historical background of this collaboration in the specific area of health security, using country examples to demonstrate lessons learnt and the evolution and pairing of Tripartite programmes and processes to jointly develop and deliver capacity strengthening tools to countries and strengthen performance for iterative evaluations. Evaluation frameworks, such as the International Health Regulations (IHR) Monitoring and Evaluation Framework, the WOAH Performance of Veterinary Services (PVS) Pathway and the FAO multisectoral evaluation tools for epidemiology and surveillance, support a shared global vision for health security, ultimately serving to inform decision making and provide a systematic approach for improved One Health capacity strengthening in countries. Supported by the IHR-PVS National Bridging Workshops and the development of the Tripartite Zoonoses Guide and related operational tools, the Tripartite and now Quadripartite, are working alongside countries to address critical gaps at the human-animal-environment interface.

Monocyte progenitors give rise to multinucleated giant cells.

The immune response to mycobacteria is characterized by granuloma formation, which features multinucleated giant cells as a unique macrophage type. We previously found that multinucleated giant cells result from Toll-like receptor-induced DNA damage and cell autonomous cell cycle modifications. However, the giant cell progenitor identity remained unclear. Here, we show that the giant cell-forming potential is a particular trait of monocyte progenitors. Common monocyte progenitors potently produce cytokines in response to mycobacteria and their immune-active molecules. In addition, common monocyte progenitors accumulate cholesterol and lipids, which are prerequisites for giant cell transformation. Inducible monocyte progenitors are so far undescribed circulating common monocyte progenitor descendants with high giant cell-forming potential. Monocyte progenitors are induced in mycobacterial infections and localize to granulomas. Accordingly, they exhibit important immunological functions in mycobacterial infections. Moreover, their signature trait of high cholesterol metabolism may be piggy-backed by mycobacteria to create a permissive niche.

Platelets Restrict the Oxidative Burst in Phagocytes and Facilitate Primary Progressive Tuberculosis.

Rationale: Platelets are generated in the capillaries of the lung, control hemostasis, and display immunological functions. Tuberculosis primarily affects the lung, and patients show platelet changes and hemoptysis. A role of platelets in immunopathology of pulmonary tuberculosis requires careful assessment.Objectives: To identify the dynamics and interaction partners of platelets in the respiratory tissue and establish their impact on the outcome of pulmonary tuberculosis.Methods: Investigations were primarily performed in murine models of primary progressive pulmonary tuberculosis, by analysis of mouse strains with variable susceptibility to Mycobacterium tuberculosis infection using platelet depletion and delivery of antiplatelet drugs.Measurements and Main Results: Platelets were present at the site of infection and formed aggregates with different myeloid subsets during experimental tuberculosis. Such aggregates were also detected in patients with tuberculosis. Platelets were detrimental during the early phase of infection, and this effect was uncoupled from their canonical activation. Platelets left lung cell dynamics and patterns of antimycobacterial T-cell responses unchanged but hampered antimicrobial defense by restricting production of reactive oxygen species in lung-residing myeloid cells.Conclusions: Platelets are detrimental in primary progressive pulmonary tuberculosis, orchestrate lung immunity by modulating innate immune responsiveness, and may be amenable to new interventions for this deadly disease.

Concordant and discordant gene expression patterns in mouse strains identify best-fit animal model for human tuberculosis.

Immunity in infection, inflammation and malignancy differs markedly in man and mouse. Still, we learn about human immunity in large extent from experimental mouse models. We propose a novel data integration approach which identifies concordant and discordant gene expression patterns of the immune responses in heterologous data sets. We have conducted experiments to compare human and murine transcriptional responses to Mycobacterium tuberculosis (Mtb) infection in whole blood (WB) as well as macrophages and compared them with simulated as well as publicly available data. Our results indicate profound differences between patterns of gene expression in innate and adaptive immunity in man and mouse upon Mtb infection. We characterized differential expression of T-cell related genes corresponding to the differences in phenotype between tuberculosis (TB) highly and low susceptible mouse strains. Our approach is general and facilitates the choice of optimal animal model for studies of the human immune response to a particular disease.

Chronic stress suppresses anti-tumor TCD8+ responses and tumor regression following cancer immunotherapy in a mouse model of melanoma.

Animal tumor models and human cancer studies have provided convergent evidence that chronic psychological stress plays a decisive role in modulating anti-tumor T cell immunity. However, whether chronic stress also affects anti-cancer vaccine strategies that rely on the induction of functional tumor-specific TCD8+ cells has not been investigated yet. In this study we provide direct evidence that chronic stress suppresses the therapeutic efficacy of a biodegradable poly(d,l-lactide-co-glycolide) microsphere (PLGA-MS) based cancer vaccine in a murine melanoma model. Exposure of mice to social disruption stress (SDR), a well-established model mimicking psychological chronic stress in humans, significantly impaired tumor protection in response to cancer vaccination under both prophylactic and therapeutic conditions. Vaccine failure in stressed mice correlated with significantly reduced generation of interferon-γ (IFN-γ)-producing TCD8+ effectors and CTL-mediated killing. Phenotypic analysis of dendritic cells (DCs) revealed that both migratory and lymphoid-resident DCs failed to undergo full maturation upon antigen uptake. Notably, decreased DC maturation was associated with a significant impairment of peripheral DCs to migrate to draining LNs and to prime subsequent TCD8+ responses in vivo. In conclusion, chronic stress represents an important factor mediating immunosuppression in cancer-vaccinated hosts by impairing DC functions and subsequent TCD8+ priming. Potentially, the mechanistic insights gained in this study open new avenues in utilizing the full potential of anti-cancer vaccination strategies.

Lung-residing myeloid-derived suppressors display dual functionality in murine pulmonary tuberculosis.

RATIONALE: Myeloid cells encompass distinct populations with unique functions during homeostasis and disease. Recently, a novel subset of innate cells, myeloid-derived suppressor cells (MDSCs), has been described in cancer, which suppresses T-cell responses and fosters disease progression. The role of MDSCs in infection is insufficiently addressed. OBJECTIVES: To examine the presence and function of MDSCs during experimental pulmonary tuberculosis (TB) and further understand the immunologic consequences of direct interactions between MDSCs and lung bacterial pathogens. METHODS: Using cell-based approaches and experimental mouse models for pulmonary TB we characterized MDSCs as novel myeloid populations directly interacting with Mycobacterium tuberculosis (Mtb). MEASUREMENTS AND MAIN RESULTS: MDSCs readily phagocytosed Mtb, and released proinflammatory (IL-6, IL-1α) and immunomodulatory (IL-10) cytokines while retaining their suppressive capacity. MDSCs were identified at the site of infection in the lung in disease-resistant and -susceptible mice during pulmonary TB. Excessive MDSC accumulation in lungs correlated with elevated surface expression of IL-4Rα and heightened TB lethality, whereas targeted depletion of MDSCs ameliorated disease. CONCLUSIONS: Our data reveal that MDSCs provide a niche for pathogen survival and tailor immunity in TB. These findings suggest MDSCs as amenable targets for host-directed therapies and emphasize them as cellular-immune regulators during chronic inflammatory conditions, including chronic infections and microbial complications of neoplastic disorders.