The Innate Immune Protein Calprotectin Interacts With and Encases Biofilm Communities of and .

Calprotectin is a transition metal chelating protein of the innate immune response known to exert nutritional immunity upon microbial infection. It is abundantly released during inflammation and is therefore found at sites occupied by pathogens such as and . The metal limitation induced by this protein has previously been shown to mediate and co-culture. In addition to the transition metal sequestration role of calprotectin, it has also been shown to have metal-independent antimicrobial activity direct cell contact. Therefore, we sought to assess the impact of this protein on the biofilm architecture of and in monomicrobial and polymicrobial culture. The experiments described in this report reveal novel aspects of calprotectin's interaction with biofilm communities of and discovered using scanning electron microscopy and confocal laser scanning microscopy. Our results indicate that calprotectin can interact with microbial cells by stimulating encapsulation in mesh-like structures. This physical interaction leads to compositional changes in the biofilm extracellular polymeric substance (EPS) in both and .