Human polymorphonuclear leukocytes release leukotriene B4 during phagocytosis of Staphylococcus aureus

We studied release of leukotriene B4 (LTB4) by human polymorphonuclear leukocytes (PMNs) during phagocytosis of staphylococci in the presence or absence of arachidonic acid. The 12 X 10(7) PMNs incubated with 3 X 10(9) opsonized S. aureus and 50 microM arachidonic acid released 1.45 +/- 0.42 nmol LTB4. No LTB4 was detected after stimulation of PMNs with S. aureus or arachidonic acid by themselves. However, by increasing the concentration of arachidonic acid to 200 or 400 microM, 1.22 +/- 0.45 and 1.98 +/- 0.49 nmol LTB4, respectively, was released by PMNs. The effect of different bacteria-PMN ratios on LTB4 production was also studied. LTB4 varied from 0.3 to 2.0 nmol when bacteria/PMN ratios increased from 5 to 50 (respectively) in the presence of 50 microM arachidonic acid. Thus, phagocytizing PMNs produce LTB4 in the presence of arachidonic acid, and its production is dependent on the number of bacteria phagocytized.