Neutrophil chemotaxis and adherence in vitro and localization in vivo in rabbits with Staphylococcus aureus abscesses

Decreased neutrophil (PMN) function may contribute to an altered host defense system in hosts with bacterial abscesses but has not been well correlated to in vivo outcome. We have found that blood PMNs from rabbits with chronic (2-week) experimental Staphylococcus aureus abscesses have decreased chemotaxis in response to an S. aureus supernatant (370 +/- 130 microns migration vs 570 +/- 180 microns, p less than 0.05) and decreased adherence (11.5% +/- 13.2% vs 32.9% +/- 18.6%, p less than 0.005) compared with PMNs from animals with acute (24-hour) abscesses. No differences were found in chemokinesis, random migration, and chemotaxis in response to zymosan-activated serum. No plasma inhibitors of PMN chemotaxis or inhibitors of chemotaxins were found. Although animals with chronic abscesses had higher levels of circulating chemotaxins, in both groups of animals abscess chemotaxin levels were greater than the plasma chemotaxin level. Animals with a concomitant chronic abscess had less PMN influx into an acute abscess but also less bacterial growth within the abscess than animals without a concomitant chronic abscess. We conclude that rabbits with chronic staphylococcal abscesses have decreased chemotaxis and adherence measured in vitro and decreased PMN localization in vivo. In this model, these functions were not associated with increased bacterial proliferation in vivo.