Magne K. Fagerhol

Affiliates

Department of Gastroenterology, Ullevaal University Hospital, Oslo, Norway

Abstract

Background: Lectins are carbohydrate binding proteins abundant in plants and seeds showing specific binding to certain sugars or oligosaccharides, for instance on cell surfaces. They function as recognition factors for cells, microbes and proteins, and are used by viruses for binding to and infect our cells. I hypothesized that calprotectin might bind lectins and thereby have a protective function.
Methods: Commercially available lectins dissolved in tris buffered saline (TBS) were used for coating of microwells in 96 well plates over night at RT. Remaining protein binding sites on the plastic surface were blocked by incubation with TBS added 1 per cent bovine serum albumin for 40 min. Subsequently, calprotectin or fecal extracts were added wells and incubated for 40 min at RT. After washing, wells were added enzyme (HRP) labelled mixed monoclonal anti-calprotectin and incubated again. After washing, wells were added HRP substrate, and reading of OD at 450 nm was performed after 15 to 30 min.
Results: recombinant calprotectin, but not its subunit S100A9, binds strongly to many lectins. The binding of fecal calprotectin varied between fecal extracts and lectins PNA, ConA, Lens c and Phas v.
Conclusion: For the fist time it has been found the calprotectin, even i stool extracts, can bind to diffferent lectins using a simple ELISA procedure. This allows further studies on possible associations with diagnoses, localization and disease activities. Hypothetically, the antimicrobial activity of calprotectin may be enhanced by its binding to lectins on microbes.