Paper accepted: Transkingdom mechanism of MAMP generation by chitotriosidase (CHIT1) feeds oligomeric chitin from fungal pathogens and allergens into TLR2-mediated innate immune sensing

Today, another of the manuscripts in Margareta Hellmann’s doctoral thesis has been accepted for publication in the renowned journal Frontiers in Immunology. This paper has been growing over long years, it has a long title and a long list of co-authors. The study was coordinated by Prof. Alex Weber from the Institute of Immunology at the University of Tübingen. The field of chitins and chitosans as fungal PAMPs triggering immune reactions in their hosts is one of the rare exceptions where research in plant biology is leading and medical research is following our lead. That’s how it was with the molecular stealth hypothesis, when the conversion of chitin to chitosan was recognised as a fungal pathogenicity strategy to hide from the host’s chitin-triggered immune system. And that’s how it is now again when understanding the role of host chitinases in generating diffusible, PAMP-active chitin oligomers, and of co-receptors presenting them to the chitin receptors triggering immune responses. The receptors and co-receptors involved differ fundamentally between plants and mammals, but the principle is the same. Margareta’s doctoral project was situated right at this pivotal point between fungal pathogenicity and host immunity, enzymatic synthesis and degradation of chitins and chitosans, structural and functional analyses of chitosans. In plants, the ‘priming’ activity of specific chitosan oligomers can be exploited to ‘vaccinate’ plants against disease and stress. And the well-known ‘defence priming’ mechanisms of plants may have its equivalent in the recently observed ‘trained immunity’ mechanisms of animals and humans, a non-specific, broad-spectrum immune memory. After all, will there finally be a vaccination against stress? One can always dream…