Secondary granules

Lactoferrin, a protein found in secondary granules of polymorphonuclear cells, was observed to be mildly to moderately elevated in the stools of children with endemic cryptosporidiosis [91] and healthy adult volunteers with experimental infection [92], Indeed, in another study of malnourished children in Haiti, cryptosporidiosis was noted to stimulate an inflammatory response, as evidenced by elevated IL-8, TNF-a, lactoferrin, IL-13 and IL-10 [93]. Further studies are needed to elucidate the role of inflammatory mediators in the development of prolonged diarrhea, malabsorption and malnutrition in immunocompromised hosts and children in endemic areas. 

These cells are characterised by the fact that they synthesise and accumulate large numbers of peroxidase-negative granules, termed the specific (or secondary) granules. Specific granules are either spherical (200-nm diameter)... 

Cellular Activation. Chemokines are potent cell activators after binding to the appropriate G protein-linked, seven-transmembrane spanning receptors, chemokines elicit transient intracellular calcium flux, actin polymerization, oxidative burst with release of superoxide free radicals, exocytosis of secondary granule constituents, and increased avidity of integrins for their adhesion molecules (Dl, E2). 

PF4. CXCL4. Belongs to inflammatory cytokines family, mediates the relationship between monocytes and endothelial cells, induces neutrophil adhesion and secondary granule exocytosis, and influences macrophages adhesion to endothelial cell by triggering monocyte arrest in atherosclerotic arteries... 

The effector role of the eosinophil in the pathogenesis of asthma is mediated in part by the release of eosinophil-specific granular proteins. The four principal basic proteins in the secondary granules of the eosinophil are MBP, EPO, ECP and EDN. 

A. M. (1993). Ultrastructural immunogold localization of tumor necrosis factor to the matrix compartment of human eosinophil secondary granules. J. Histochem. Cytochem. 41, 1611-1615. 

Xu SY, Carlson M, Engstrom A, Garcia R, Peterson CG, Venge P (1994) Purification and characterization of a hitman neutrophil lipocalin (HNL) from the secondary granules of human neutrophils. Scand J Clin Lab Invest 54(5) 365-376... 

Neutrophil secondary granules contain lL-12 [50, 51], an immune-modulatory cytokine able to exert antiangiogenic effects possibly mediated... 

Iron is then reoxidized to Fe in an aerobic environment and coordinated by lactoferrin released from the secondary granules of neutrophils. The resultant lactoferrin-Fe is taken up by specific receptors on macrophages (102,103). The transport of the iron, implicated as the target of neutrophilic inflammation, concludes as the metal is stored in ferritin (104,105). This deposition in the macrophage is histologically detected as a sideromacrophage and can be a reliable marker of neutrophilic inflammation (102,106,107). 

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