According to a press release, the human 3D models for the upper and lower respiratory tract developed by the scientists at the Medical University of Innsbruck can be used to simulate and track interactions between the coronavirus and the immune system. "Our human system allows a very realistic replica of the multilayered epithelium of the airways and lungs. In these highly differentiated 3D tissue systems, we have now used SARS-CoV-2 as the pathogen and observed, virtually in live mode, how epithelial cells of the respiratory tract release the soluble complement fragments C5a and C3a," said infection biologist Professor Doris Wilflingseder. 

These so-called anaphylatoxins, which were also found to be elevated in COVID-19 patients with a critical course, trigger a strong inflammatory reaction, so that pro-inflammatory messenger substance (cytokines) are produced at the site of infection. This cytokine storm finally calls further immune cells to the scene - a tissue-damaging and life-threatening infection event (hyper inflammation), which has already been observed clinically and for the first time without animal experiments in the laboratory.

To see whether inhibition of the anaphylatoxins C3a and C5a could prevent hyper inflammation, the scientists used chemical blockers. These blockers showed a convincing effect and protected against the destruction of the lung tissue.

Original publication:
Wilfried Posch, Jonathan Vosper, Asma Noureen, et al (2021). C5aR inhibition of nonimmune cells suppresses inflammation and maintains epithelial integrity in SARS-.
CoV-2-infected primary human airway epithelia. J. Allergy Clin. Immunol.; 2021 DOI: https://doi.org/10.1016/j.jaci.2021.03.038

Source:
https://www.i-med.ac.at/mypoint/news/753531.html