Superoxide anion production in glass-adherent polymorphonuclear leukocytes and its relationship to calcium movement.

Abstract

The production of superoxide anion (O2-.) was measured in relation to 45Ca movement in glass-adherent polymorphonuclear leukocytes (PMNs), and the results were compared with those obtained by ourselves and others on PMNs in suspension. In adherent PMNs, O2-. production stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP) was of rapid onset and short duration; this was also true of PMNs in suspension. However, O2-. production was insensitive to the concentration of extracellular calcium. Both in adherent and non-adherent PMNs, O2-. production stimulated with phorbol myristate acetate (PMA) had a latency time and was of long duration. In adherent PMNs, pretreatment with PMA potentiated the FMLP-induced O2-. production by lengthening its duration without changing its initial rate. In adherent PMNs (10(-10)-10(-7) M) FMLP induced a fast but transient dose-dependent increase in 45Ca within 1 min, whereas PMA only released 45Ca about 5 min after its addition to the cell culture medium. Pretreatment of PMNs with 10 or 100 ng/ml PMA for 3 min before stimulation by 10(-7) M FMLP reduced the 45Ca efflux observed with FMLP alone. We conclude that O2-. production by adherent PMNs cannot simply be related to Ca2+ movement. In comparison with non-adherent cells, adherence seemed to interfere with the characteristics of both calcium and O2-. generation, probably by modifying the cytoskeleton.