Modelling early events in Mycobacterium bovis infection using a co-culture model of the bovine alveolus

Abstract

Bovine tuberculosis (bTB), a zoonosis mainly caused by Mycobacterium bovis has severe socio-economic consequences and impact on animal health. Host–pathogen interactions during M. bovis infection are poorly understood, especially early events which are difficult to follow in vivo. This study describes the utilisation of an in vitro co-culture model, comprising immortalised bovine alveolar type II (BATII) epithelial cells and bovine pulmonary arterial endothelial cells (BPAECs). When cultured at air–liquid interface, it was possible to follow the migration of live M. bovis Bacille Calmette-Guérin (BCG) and to observe interactions with each cell type, alongside cytokine release. Infection with BCG was shown to exert a detrimental effect primarily upon epithelial cells, with corresponding increases in IL8, TNFα, IL22 and IL17a cytokine release, quantified by ELISA. BCG infection increased expression of CD54, MHC Class I and II molecules in endothelial but not epithelial cells, which exhibited constitutive expression. The effect of peripheral blood mononuclear cell conditioned medium from vaccinated cattle upon apical-basolateral migration of BCG was examined by quantifying recovered BCG from the apical, membrane and basolateral fractions over time. The numbers of recovered BCG in each fraction were unaffected by the presence of PBMC conditioned medium, with no observable differences between vaccinated and naïve animals.

A bovine pulmosphere model and multiomics analyses identify a signature of early host response toMycobacterium tuberculosisinfection

“…Additionally, the bovine pulmosphere model possesses a scientific potential that extends to minimizing the need for live animals in research. In the context of bovine TB research, a notable challenge arises from the limited understanding of the initial stages of TB pathophysiology within the bovine lung due to the scarcity of studies, which is attributed in part to the intricate nature of conducting experimental infections in large animals within a bio-contained setting [14]. The pulmosphere model holds promise for reducing the number of animals required for basic research investigations on bovine TB and serves as an ethical and valuable substitute for large animal testing.…”

“…In addition, mouse and human macrophage cell lines have also been employed to study host responses to bovine tubercle bacilli [12]. However, the variation in host responses among different species and mycobacterial strains underscores the importance of developing speciesspecific disease models to unravel intricate events during TB pathogenesis [13][14][15][16].…”

Mycobacterial Infection of Precision-Cut Lung Slices Reveals Type 1 Interferon Pathway Is Locally Induced by Mycobacterium bovis but Not M. tuberculosis in a Cattle Breed

“…In this study, the authors detected the production of IL-8, TNFα, IL-22, and IL-17a. One limitation of this model was epithelial cell death, which occurred shortly after infection (48). As a physiological model, PCLS could help in understanding the early orchestration of the local inflammatory response in the lung in response to mycobacterial infection.…”

Mycobacterial infection of precision cut lung slices reveals that the type 1 interferon pathway is locally induced by Mycobacterium bovis but not M. tuberculosis in different cattle breeds

“…The role of Type II pneumocytes during Mb infection in cattle is not well known. Also, most of the available knowledge on the role of bovine macrophages (MPs) during Mb infection comes from studies conducted with monocytes sampled from blood and derived as MPs during in vitro culture [25].…”