Viral-bacterial co-infections of the differentiated airway epithelium by pathogens associated with the bovine respiratory disease complex

• Applicants: Professor Dr. Georg Herrler; Dr. Jochen Meens
• Subject Area: Veterinary Medical Science
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 313942933

Co-infections in the respiratory tract play an important role in modern intensive production systems of agricultural animals. Control of co-infections is a challenging task, since pathogenesis is much more complex as compared to mono-infections. Though this has been known for many years, little is known about the molecular mechanisms of interactions between pathogens and the host in co-Infections. It is very difficult to study this in animal infections and, therefore, it is important to develop suitable in vitro models which mimic the in vivo situation as closely as possible. In the proposed project, we will analyze the co-infection of airway epithelial cells by important pathogens of the bovine respiratory tract. The pathogens analyzed comprise two viruses and three bacteria that are all considered to be involved the bovine respiratory disease complex: bovine respiratory synzytial virus (BRSV), bovine parainfluenzavirus 3 (BPIV3), Pasteruella multocida, Mannheimia haemolytica und Mycoplasma bovis. This project is based on preliminary work in which we analyzed the viral mono-infection of differentiated airway epithelial cells. Using two cultural systems for differentiated respiratory epithelial cells, precision-cut lung slices and air-liquid-interface cultures, we found that infection of airway cells by BPIV3 is very efficient and has a detrimental effect on the epithelium. By contrast, cells of the respiratory epithelium turned out to be largely resistant against an infection by BRSV. Aim of the proposed project is first to analyze the bacterial mono-infection which has already been started in the case of M. bovis. This is followed by an inverstigation of the co-infection. The following will be addressed: (i) Does the detrimental effect of the BPIV3 infection favor a subsequent infection by one of the three bacterial agents? (ii) Does the bacterial infection render the airway cells susceptible for a subsequent infection by BRSV? The expected results will increase our understanding how S. suis how important respiratory pathogens interact in the bovine lung to induce the symptoms characteristic for the bovine respiratory disease complex.

• DFG Programme: Research Grants