Effect of Coxiella burnetii on the stimulation of hexose monophosphate shunt and on superoxide anion production in human polymorphonuclear leukocytes.

Killed Coxiella burnetii (C.b.) cells in phase II but not in phase I had a mild stimulatory effect on hexose monophosphate shunt (HMPS) and superoxide anion production by human polymorphonuclear (PMN) leukocytes. Preincubation of C.b. cells of either phase with serum of a leukocyte donor lacking detectable antibodies to C.b. did not affect the studied activities of PMN leukocytes. In contrast, both HMPS stimulation and superoxide production were enhanced by specific opsonization of C.b. cells with rabbit immune sera containing corresponding phase I and/or phase II antibodies. Stimulatory effect was observed also with lipopolysaccharide-protein-phospholipid (LPS-Pr-Pl) complex but not with lipopolysaccharide-protein (LPS-Pr) complex and with purified lipopolysaccharide (LPS) isolated from phase I C.b. cells. Possible consequences of these findings for explanation of C.b. resistance to intracellular killing by professional phagocytes are discussed.