Related Experiment Videos
The effect of adherence on the generation of reactive oxygen species by human neutrophilic granulocytes
1Abteilung für Experimentelle Dermatologie, Universität-Hautklinik, Freiburg, FRG.
Abstract:
Human neutrophilic granulocytes (PMN) suspended in protein containing salt solution or adherent on protein coated nylon fibers were tested for the production of H2O2 and O2- in response to various PMN stimulants. Upon stimulation with the chemotactic factors formyl-methionyl-leucyl-phenylalanine, C5a and platelet activating factor, the non-chemotactic ionophore A23187, and the chemotaxis inhibitors tumor necrosis factor (TNF alpha) and lymphotoxin (TNF beta) adherent PMN produced considerably more reactive oxygen metabolites than suspended cells. The relative amounts of the two metabolites varied with the stimulus and its concentration, TNF alpha and TNF beta favoring H2O2 production, C5a eliciting more O2- than H2O2 and the other active stimulants being in between. Leukotriene B4 and a novel monocyte-derived chemotaxin were inactive in releasing either oxygen derivative from adherent or suspended PMN. The data indicate that attachment of PMN to endothelial cells or to connective tissue substances can strongly enhance its ability to respond to a given stimulus with the production of reactive oxygen metabolites. The findings may in part explain the "priming" phenomenon since many PMN-priming mediators increase the cells' adherence.
Insights
Adherent human neutrophilic granulocytes (PMN) produce more reactive oxygen metabolites than suspended cells. Cell attachment enhances PMN response to stimulants, potentially explaining the "priming" phenomenon.
Area of Science:
- Immunology
- Cell Biology
Background:
- Human neutrophilic granulocytes (PMN) are crucial immune cells.
- Their production of reactive oxygen species (ROS) plays a role in host defense.
- Factors influencing PMN ROS production are of significant interest.
Purpose of the Study:
- To investigate the effect of cell adherence on PMN production of hydrogen peroxide (H2O2) and superoxide (O2-).
- To compare ROS production in adherent versus suspended PMN stimulated by various factors.
- To explore the implications for PMN priming.
Main Methods:
- Human PMN were tested in both suspended and adherent states (on nylon fibers).
- Cells were stimulated with various agents including chemotactic factors, ionophore A23187, and TNF-alpha/beta.
- Production of H2O2 and O2- was measured in response to stimuli.
Main Results:
- Adherent PMN produced significantly more ROS (H2O2 and O2-) than suspended PMN across various stimuli.
- The type and concentration of stimulus influenced the relative amounts of H2O2 and O2- produced.
- TNF-alpha and TNF-beta favored H2O2, while C5a favored O2-.
Conclusions:
- PMN adherence to surfaces like endothelial cells strongly enhances their ROS-producing capacity.
- This enhanced responsiveness may contribute to the observed