Different sensitivities of the responses of human neutrophils stimulated with immune complex and C5a anaphylatoxin to pertussis toxin.

When stimulated with immune complex or C5a anaphylatoxin, human neutrophils undergo an increase in the concentration of intracellular Ca2+ [( Ca2+]i) that precedes the onset of superoxide (O2-) production. The extracellular Ca2+ is required for the O2- production of neutrophils stimulated by C5a, but is only partially required for those by immune complex. The addition of pertussis toxin to neutrophils does not inhibit the rise in [Ca2+]i and O2- production induced by immune complex but does inhibit those induced by C5a. These results suggest that a different sequence of reaction is involved by different stimulants, the anaphylatoxin and immune complex.