Expression and secretion of ficolin β by porcine neutrophils

Identification, cloning and tissue localization of a rainbow trout (Oncorhynchus mykiss) intelectin-like protein that binds bacteria and chitin

“…Plasma forms of human ficolins are mainly synthesized in the liver [30,35], whereas mucosal forms secreted onto epithelial surfaces are produced by unciliated bronchial epithelial cells [35]. Porcine plasma ficolin a which binds Actinobacillus pleuropneumoniae (serotype 5b) [25,36] has been identified from epithelial cytoplasm of intestinal crypts and lungs [36] while porcine ficolins b are found in neutrophils [37]. Similarly, mucosal cruciform lectins such as human lung surfactant protein D (SP-D) can agglutinate or neutralize infectious microbes [38,39] and enhance microbial clearance via phagocytosis and mucociliary transport [40].…”

Ficolins: Novel pattern recognition molecules of the innate immune response

“…Ficolin-a is expressed in liver, bone marrow, spleen, lung (Ohashi and Erickson, 1998) and very weakly in the uterus (Ichijo et al, 1993), whereas ficolin-b is expressed in bone marrow and neutrophils (Brooks et al, 2003b). Ficolina and -b share 81-84% identity at the amino acid level.…”

“…Ficolina and -b share 81-84% identity at the amino acid level. Ficolin-a is the major plasma ficolin and consists of N-glycosylated subunits of 35 kDa (Ohashi and Erickson, 1998) while ficolin-b has an apparent molecular weight of 39 kDa and was found to be synthesized, stored, and secreted by porcine neutrophils but not by peripheral blood monocytes or platelets (Brooks et al, 2003b). Ficolin-b is present in both cytoplasmatic and membrane fractions of neutrophil preparations but its subcellular distribution has not been shown.…”

“…On the other hand, it seems that ficolin-b might function locally as a secreted collagenous defense lectin at sites of inflammation where neutrophils are activated. The secreted contents of PMA-activated neutrophils are bactericidal and ficolinb may participate with other antibacterial neutrophil products in tissue antisepsis (Brooks et al, 2003b). However, the microbial targets for ficolin-b are not known and, in general, it has not been shown yet whether porcine ficolins can activate the complement system.…”

Human L-Ficolin (Ficolin-2) and Its Clinical Significance

“…Although first discovered in uterine tissue, porcine ficolin- α is more abundant in liver and blood where two isoforms, “little ficolin” (Mr~400 000) and “big ficolin” (Mr~800 000) were described [7]. Ficolin- β , with around 80% identity to ficolin- α , was found to be expressed mainly in neutrophils [8]. …”