Respiratory explants as a model to investigate early events of contagious bovine pleuropneumonia infection

Abstract

Contagious bovine pleuropneumonia (CBPP) is a severe disease caused by Mycoplasma mycoides subsp. mycoides (Mmm). Knowledge on CBPP pathogenesis is fragmented and hampered by the limited availability of laboratory animal and in vitro models of investigation. The purpose of the present study is to assess respiratory explants as useful tools to study the early stages of CBPP. Explants were obtained from trachea, bronchi and lungs of slaughtered cattle, tested negative for Mycoplasma spp. and for the major bacterial and viral respiratory pathogens. The interaction of Mmm with explant cells was studied by immunohistochemistry (IHC), double-labelling indirect immunofluorescence (DLIIF) and laser scanning confocal microscopy (LSCM). Mmm capability to survive and proliferate within the explants was evaluated by standard microbiological procedures. Finally, the putative cellular internalization of Mmm was further investigated by the gentamicin invasion assay. IHC and DLIIF indicated that Mmm can colonize explants, showing a marked tropism for lower airways. Specifically, Mmm was detected on/inside the bronchiolar and alveolar epithelial cells, the alveolar macrophages and the endothelial cells. The interaction between Mmm and explant cells was abolished by the pre-incubation of the pathogen with bovine anti-Mmm immune sera. Mmm was able to survive and proliferate in all tracheal, bronchial and lung explants, during the entire time course of the experiments. LSCM and gentamicin invasion assay both confirmed that Mmm can enter non-phagocytic host cells. Taken together, our data supports bovine respiratory explants as a promising tool to investigate CBPP, alternative to cattle experimental infection.Electronic supplementary materialThe online version of this article (10.1186/s13567-017-0500-z) contains supplementary material, which is available to authorized users.

SARS-CoV-2 replicates in respiratory ex vivo organ cultures of domestic ruminant species

“…Tracheal and lung EVOCs culture and viability were assessed as described previously ( Di Teodoro et al, 2018 , 2019 ). Briefly, at the slaughterhouse, the cranial portion of trachea and the right lung were immediately collected after the stunning and bleeding of the animals.…”

Pro-Inflammatory Response of Bovine Polymorphonuclear Cells Induced by Mycoplasma mycoides subsp. mycoides

“…Although investigated for long time, the pathogenesis of CBPP remains mostly unknown. This is due to several reasons including difficulties and costs to reproduce the disease experimentally in the natural host and the lack of appropriate laboratory animal models (27). Recently, ex vivo models based on bovine respiratory explants were developed, providing additional knowledge about host-specificity of Mmm (28) and its selective tropism for lower respiratory airways (bronchioles and alveoli) which represent the primary infection site (27).…”

“…This is due to several reasons including difficulties and costs to reproduce the disease experimentally in the natural host and the lack of appropriate laboratory animal models (27). Recently, ex vivo models based on bovine respiratory explants were developed, providing additional knowledge about host-specificity of Mmm (28) and its selective tropism for lower respiratory airways (bronchioles and alveoli) which represent the primary infection site (27). Acute-subacute CBPP pulmonary lesions from infected animals are characterized by a massive infiltration of inflammatory cells, with a relevant component represented by neutrophil granulocytes, together with the presence of high levels of some pro-inflammatory factors (TNFα, IL-1β, and IL-17A) (29).…”

Host-Pathogen Interactions of Mycoplasma mycoides in Caprine and Bovine Precision-Cut Lung Slices (PCLS) Models

“…Similarly, we did not detect Mmm Afadé adherent to endothelial cells of the blood vessels present in the PCLS and from cattle infected with Mmm Afadé (Data not shown). However, Di Teodoro and colleagues [56] reported Mmm strongly adherent to endothelial cells. The different observations might be due to different experimental systems, tissue composition (in respiratory explants, trachea, bronchus, and lung parenchyma were separately used for the study, whereas PCLS includes bronchioles and lung parenchyma together), culture conditions, initial duration of infection (1 h vs. 4 h), thickness of tissue samples (1mm vs. 0.3 mm), preparation of samples and reproducibility of tissue size (manual sections vs. automated slicer), and media composition.…”