https://www.selleckchem.com/products/PHA-739358(Danusertib).html The complement system constitutes an important part of the innate immune system. and the ficolins are soluble pattern recognition molecules that contribute to complement activation via the lectin pathway. During previous experiments with ficolin-2 and ficolin-3, we have observed that the molecules may interact. We therefore hypothesized the existence of stable ficolin-2/-3 heterocomplexes. We could demonstrate ficolin-2/-3 heterocomplexes in normal human serum and plasma by ELISA using Abs specific for ficolin-2 and ficolin-3. The formation of heteromeric protein complexes were validated by coimmunoprecipitation and Western blot analysis. When recombinant ficolin-2 and recombinant ficolin-3 were mixed, no complexes were formed. However, when coexpressing ficolin-2 and ficolin-3 in Chinese hamster ovary cells, we could detect ficolin-2/-3 heterocomplexes in the supernatant. Furthermore, we measured concentration of the ficolin-2/-3 heterocomplexes in arbitrary units in 94 healthy individuals. We also established the relationship between the concentrations of ficolin-2, ficolin-3, and the ficolin-2/-3 heterocomplexes. We observed that the concentration of the ficolin-2/-3 heterocomplex correlated significantly with ficolin-2 (ρ 0.24, p less then 0.018) and ficolin-3 concentrations (ρ 0.46, p less then 0.0001). In conclusion, we describe a novel protein complex between ficolin-2 and ficolin-3 present in serum and plasma, which might be of additional biological relevance apart from the native ficolin-2 and ficolin-3 molecules. Copyright © 2020 by The American Association of Immunologists, Inc.Major myeloid cell functions from adhesion to migration and phagocytosis are mediated by integrin adhesion complexes, also known as adhesome. The presence of a direct integrin binding partner Kindlin-3 is crucial for these functions, and its lack causes severe immunodeficiency in humans. However, how Kindlin-3 is inco