Comparison of oxidant production by bovine neutrophils and monocyte-derived macrophages stimulated with Brucella abortus strain 2308.

Oxidant production by bovine monocyte-derived macrophages and neutrophils was compared after stimulation with phorbol myristate acetate (PMA), opsonized zymosan (OZ), and B. abortus opsonized with naive-autologous, reactor, or fetal bovine sera. Neutrophils responded more rapidly to all stimuli and produced up to 100-fold greater oxidant than did equal numbers of bovine monocyte-derived macrophages. Macrophages and neutrophils stimulated with PMA, OZ, and reactor-opsonized B. abortus had higher mean oxidant production than phagocytes exposed to B. abortus opsonized with autologous sera, fetal bovine serum, or nonopsonized bacteria. Stimulation of macrophages by opsonized zymosan, buffer, and B. abortus opsonized with autologous sera, reactor serum, or fetal bovine serum resulted in low levels of oxidant production that were not significantly different. Only PMA caused a significantly higher level of oxidant production by macrophages.