Selected β-Glucans Act as Immune-Training Agents by Improving Anti-Mycobacterial Activity in Human Macrophages: A Pilot Study.

Epigenetic reprogramming of innate immune cells by β-glucan in a process called trained immunity leads to an enhanced host response to a secondary infection. β-Glucans are structural components of plants, algae, fungi, and bacteria and thus recognized as non-self by human macrophages. We selected the β-glucan curdlan from Alcaligenes faecalis, WGP dispersible from Saccharomyces cerevisiae, and β-glucan-rich culture supernatant of Alternaria and investigated whether they could produce trained immunity effects leading to an increased control of virulent Mycobacterium tuberculosis.

Corticosteroids protect infected cells against mycobacterial killing in vitro.

The effect of corticosteroids on human physiology is complex and their use in tuberculosis patients remains controversial. In a high-throughput screening approach designed to discover virulence inhibitors, several corticosteroids were found to prevent cytolysis of fibroblasts infected with mycobacteria. Further experiments with Mycobacterium tuberculosis showed anti-cytolytic activity in the 10 nM range, but no effect on bacterial growth or survival in the absence of host cells at 20 μM.

Inhibition of Tissue Matrix Metalloproteinases Interferes with -Induced Granuloma Formation and Reduces Bacterial Load in a Human Lung Tissue Model.

Granulomas are hallmarks of pulmonary tuberculosis (TB) and traditionally viewed as host-protective structures. However, recent evidence suggest that (Mtb) uses its virulence factors to stimulate the formation of granuloma. In the present study, we investigated the contribution of matrix metalloproteinases (MMPs), host enzymes that cause degradation of the extracellular matrix, to granuloma formation and bacterial load in Mtb-infected tissue.

The Cording Phenotype of Induces the Formation of Extracellular Traps in Human Macrophages.

The causative agent of tuberculosis, , shares several characteristics with organisms that produce biofilms during infections. One of these is the ability to form tight bundles also known as cords. However, little is known of the physiological relevance of the cording phenotype.

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection.

Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M.

Mycobacterium tuberculosis- induced neutrophil extracellular traps activate human macrophages.

Neutrophils activated by Mycobacterium tuberculosis (Mtb) form neutrophil extracellular traps (NETs), containing DNA and several biologically active cytosolic and granular proteins. These NETs may assist in the innate immune defense against different pathogens. We investigated whether the NET-forming neutrophils mediate an activating signal to macrophages during the early multicellular inflammatory reaction and granuloma formation.