Secretory activity of equine polymorphonuclear leukocytes: stimulus specificity and priming effects of bacterial lipopolysaccharide

Neutrophil (PMN) contributions to the acute inflammatory process and host defense include generation of bioreactive oxygen metabolites and secretion of granule enzymes. We assessed equine PMN secretion using several PMN stimuli, singly and in combination with bacterial lipopolysaccharide (LPS). LPS avidly associated with equine PMN, as shown by strong PMN labeling with FITC-conjugated LPS. LPS alone (1 or 10 μg ml −1) was a weak stimulus for PMN superoxide anion (O 2 −) generation, but preincubation with LPS followed by phorbol ester (PMA, 10 ng ml −1) significantly augmented ( P