A microscopic study of Fc gamma RIII-mediated respiratory burst in neutrophils

Respiratory burst response of peritoneal leukocytes adhering to titanium and stainless steel

Titanium sheets, made hydrophilic by oxidative cleaning or hydrophobic by treatment with butanol, and stainless steel sheets with different patterns of pores (straight phi = 0.8 mm) were implanted into the peritoneal cavity of mice. The implants were removed after 2 h, and the surface-adhering leukocytes were stained with propidium iodide and fluorescein diacetate to quantitate cell adhesion and to indicate the presence of leaks in the cell membrane. The ability of the surface-adhering leukocytes to mount a respiratory burst response after stimulation with PMA or zymosan was measured by chemiluminiscence. The results show that stainless steel without pores induces membrane leakage in 80% of the surface-adhering leukocytes compared with 65% of cells adhering to porous steel. Hydrophilic titanium induces membrane leakage in 48% of the surface-adhering leukocytes compared with 19% of cells adhering to hydrophobic titanium. The respiratory burst response of the surface-adhering leukocytes stimulated with PMA was attenuated on stainless steel and hydrophilic titanium compared with hydrophobic titanium. Thus, butanol treatment of titanium and pores in stainless steel increase the biocompatibility of the materials.

The respiratory burst response of surface-adhering leukocytes. A key to tissue engineering

Biomaterials implanted into tissue will participate in the complex signalling between cells during wound healing. Recent studies have revealed that crucial cellular signalling pathways are regulated by the extra- and intracellular redox states and that reactive oxygen species function as intercellular signal molecules. Biomaterials have been shown to affect the respiratory burst response of surface-adhering leukocytes, thus interfering with major regulatory functions of cells also in surrounding tissues. The respiratory burst of surface-adhering leukocytes may thus be a key event in the understanding of biomaterial interaction with tissues, and the aim of this review is to highlight this field of research.

Fcgamma receptor-mediated phagocytosis in macrophages lacking the Src family tyrosine kinases Hck, Fgr, and Lyn

Macrophage Fcgamma receptors (FcgammaRs) mediate the uptake and destruction of antibody-coated viruses, bacteria, and parasites. We examined FcgammaR signaling and phagocytic function in bone marrow-derived macrophages from mutant mice lacking the major Src family kinases expressed in these cells, Hck, Fgr, and Lyn. Many FcgammaR-induced functional responses and signaling events were diminished or delayed in these macrophages, including immunoglobulin (Ig)G-coated erythrocyte phagocytosis, respiratory burst, actin cup formation, and activation of Syk, phosphatidylinositol 3-kinase, and extracellular signal-regulated kinases 1 and 2. Significant reduction of IgG-dependent phagocytosis was not seen in hck(-)(/)-fgr(-)(/)- or lyn(-)(/)- cells, although the single mutant lyn(-)(/)- macrophages did manifest signaling defects. Thus, Src family kinases clearly have roles in two events leading to FcgammaR-mediated phagocytosis, one involving initiation of actin polymerization and the second involving activation of Syk and subsequent internalization. Since FcgammaR-mediated phagocytosis did occur at modest levels in a delayed fashion in triple mutant macrophages, these Src family kinases are not absolutely required for uptake of IgG-opsonized particles.

Evaluation of neutrophil structure and function by electron microscopy: cytochemical studies

Methods for studying human neutrophils at the ultrastructural level by enzyme cytochemistry and immunocytochemistry are presented. The focus of these methods is on the analysis of the alkaline phosphatase-positive secretory organelle of these cells. These methods provide unique information which, when coupled with biochemical studies, provide for the most complete analysis of neutrophil structure and function.