PHAGOCYTOSIS

Phagocytosis and The Respiratory Burst

Phagocytosis and The Respiratory Burst

Discussion

The innate immune response constitutes the first line of defense against invading pathogens and consists of a variety of immune defense mechanisms including the respiratory burst of phagocytes. Respiratory burst can be used as a reliable measure of the immune response of a host, and numerous assays have been developed to measure this response in a variety of mammal and fish species (Curnutte, 1988, pp 12-15). Phagocytes, like granulocytes and macrophages, that are derived from different tissues, or grown in cell culture, have been employed in a range of assay formats employing a variety of detection methods (Sbarra & Strauss,1988, pp14-17). During the process of phagocytosis professional phagocytes undergo a vigorous respiratory burst in which they consume oxygen and convert it enzymatically to O2-, which interacts to form H2O2, then hypochlorous acid, hydroxyl radical, and other potent oxidants. It has been recognized that this process is accompanied by activation of the hexose monophosphate shunt and oxidation of GSH to GSSG through the action of GSH peroxidase and H2O2 (Lunardi et al, 2006, pp 78-85).

Phagocytosis is associated with respiratory burst producing reactive oxygen and nitrogen species. Several studies imply that erythrocytes can inhibit the respiratory burst during erythrophagocytosis. In this work we studied the mechanisms of this effect using control and in vitro peroxidized erythrocyte membranes. We demonstrated that autofluorescence of peroxidation products can be used for visualization of phagocytozed membranes by fluorescence microscopy (Nuutila, 2003, pp 10-15).

Inhibition of PMA-elicited respiratory burst was higher in the presence of peroxidized membranes. This preparation contained some extra iron from the in vitro lipid peroxidation experiment and also the products of membrane lipid peroxidation as revealed by fluorescence measurements. In the recent study it has been shown that some stable products of lipid peroxidation, ...