Not by structures alone: Can the immune system recognize microbial functions? (Gregor P. Greslehner)

One of the speakers at the “What Is Life?” symposium is going to be Gregor P. Greslehner, a philosopher of science, trained in philosophy and molecular biology. Currently, he is working as a University Assistant/Postdoc at the Department of Philosophy at the University of Vienna, contributing to Tarja Knuuttila’s ERC project “Possible Life: The Philosophical Significance of Extending Biology”. He obtained his PhD in philosophy under the supervision of Charlotte Werndl and Simon Huttegger, as well as a a MSc in molecular biology under the supervision of Michael Breitenbach at the University of Salzburg.

In his recent work, he has dealt with questions of immunology. In his paper “Not by Structures Alone: Can the immune system recognise microbial functions?”, he explores the immune system’s potential to recognise microbial functions, beginning with a historical overview of structural recognition in immunology and discussing various concepts related to structure and function. He argues that the immune system can recognise microbial functions indirectly through function-associated molecular patterns (FAMPs) and directly through biochemical activities and biological roles. Importantly, he delves into the philosophical significance of the notion of function. Besides offering a fresh perspective on how the immune system perceives microbial functions, he underscores the importance of incorporating philosophical concepts into scientific inquiry.

You may read more about the paper in the abstract below or click “Read” to access the paper in full.


A central question for immunology is: what does the immune system recognize and according to which principles does this kind of recognition work? Immunology has been dominated by the idea of recognizing molecular structures and triggering an appropriate immune response when facing non-self or danger. Recently, characterizations in terms of function have turned out to be more conserved and explanatory in microbiota research than taxonomic composition for understanding microbiota-host interactions. Starting from a conceptual analysis of the notions of structure and function, I raise the title question whether it is possible for the immune system to recognize microbial functions. I argue that this is indeed the case, making the claim that some function-associated molecular patterns are not indicative of the presence of certain taxa (‘‘who is there’’) but of biochemical activities and effects (‘‘what is going on’’). In addition, I discuss case studies which show that there are immunological sensors that can directly detect microbial activities, irrespective of their specific structural manifestation. At the same time, the discussed account puts the causal role notions of function on a more realist and objective basis.