Adhesion attenuates respiratory burst induced by different modes of triggering in resting or LPS-primed neutrophils

The effects of adherence on neutrophil superoxide anion (O₂^-) generation triggered by surface, soluble ligand, or adherence were studied. Resting-neutrophils adhered to the uncoated tubes resulting in O₂^- generation, but not on plasma-, fibrinogen-, vitronectin-, fibronectin-, laminin-, collagen-, or poly HEMA-coated surfaces. Enhanced N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated O₂^- generation by LPS-primed-neutrophils was induced by the incubation on plasma, fibrinogen, vitronectin, fibronectin, or laminin in the absence of Mg²⁺. In the presence of Mg²⁺, this response was observed in cells on collagen or poly HEMA. LPS-primed-neutrophils adhered to uncoated, BSA- or IgG-coated tubes and did not respond to fMLP, indicating that the fMLP-response of LPS-primed-neutrophils was suppressed by adherence. Upon incubation on plasma, fibrinogen, vitronectin, fibronectin in the presence of Mg²⁺, LPS-primed-neutrophils showed O₂^- generation. Upon incubation on collagen or poly HEMA, the primed-neutrophils neither generated O₂^- nor adhered. We found that O₂^- response of LPS-primed-neutrophils was attenuated depending on the time of exposure to plasma-coated surface. This attenuation was evident on plasma or fibrinogen, but not on collagen in the presence of Mg²⁺, indicating that O₂^- generation by LPS-primed-neutrophils was attenuated dependent on adherence but not on Mg²⁺. Thus, adhesion attenuated the O₂^- generation triggered by both soluble (fMLP) and insoluble (surface) stimuli.