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Granularin, a novel molluscan opsonin comprising a single vWF type C domain is up‐regulated during parasitation
Author(s) -
Smit August B.,
Jong-Brink Marijke,
Li Ka Wan,
Sassen Marion M. J.,
Spijker Sabine,
Elk René,
Buijs Stèphanie,
Minnen Jan,
Kesteren Ronald E.
Publication year - 2004
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.03-0590fje
Subject(s) - opsonin , biology , lymnaea stagnalis , phagocytosis , snail , microbiology and biotechnology , von willebrand factor , transmembrane protein , immunology , platelet , receptor , ecology , biochemistry
Snails are intermediate hosts to schistosome parasites, some of which are the main cause of human schistosomiasis (bilharzia), and have been used as models for parasite—host interactions for a long time. Here, we have characterized a novel internal defense peptide of the snail Lymnaea stagnalis , of which the relative abundance in brain tissue increases upon infection with the avian schistosome Trichobilharzia ocellata . This protein, named granularin, is secreted by granular cells, which are numerous in the connective tissue surrounding the brain. The protein is unique because it comprises only a single Von Willebrand factor type C domain that is normally found in large transmembrane and secreted extracellular matrix proteins. The granularin gene is twice up‐regulated during parasitation. Purified granularin stimulates phagocytosis of foreign particles by blood hemocytes. Together, our data indicate that granularin represents a novel protein that acts as an opsonin in the molluscan internal defense response.