Adherence-induced enhancement of the oxidative burst of human neutrophilic granulocytes: effects of the surface coat and of divalent cations.

Neutrophilic granulocytes are capable of adhering to biological or artificial surfaces. In addition to specific interactions between adherence molecules on the cell surface and corresponding structures on other cells or matrix proteins like fibronection or collagen there appeared to be non-specific attachment as well. Adherence augmentation induced by stimulation with chemotactic factors or cytokines was an active process which did not proceed at 4 degrees C and after removal of divalent cations from the medium. Adherence acted as a priming stimulus increasing the amount of superoxide anion and hydrogen peroxide produced in response to stimulation by certain chemotactic factors and cytokines. Adherence priming like priming by GM-CSF was strongly suppressed by chelation of intracellular Ca2+ ions. The two priming mechanisms differed, however, in their requirement for divalent cations in the external medium: whereas Mg2+ suppressed GM-CSF priming, it synergised with Ca2+ in the adherence-augmented oxidative burst.