The release of neutrophil chemoattractant activity by bronchoalveolar macrophages from adult and senescent mice.

To assess the effects of advanced age on the release of neutrophil chemoattractant activity by resident bronchoalveolar macrophages (BAM), cells from three strains of pathogen- and disease-free mice were secured by lung lavage and stimulated in vitro with unopsonized zymosan or the calcium ionophore, A23187. Chemoattractant release by BAM from adult (5-8 mos) and senescent (19-26 mos) C57BL/6 and DBA/2 mice in response to both stimulants was comparable; however, the generation of chemoattractant activity by BAM from senescent (18-20 mos) BALB/c mice was greater than that observed with cells from younger (4-6 mos) animals with both zymosan and A23187. In the presence of 50 microM piriprost potassium, a 5-lipoxygenase inhibitor, the release of chemoattractant activity and leukotriene B4 (LTB4) in response to zymosan and A23187 by BAM from both groups of C57BL/6 mice was significantly impaired. With BAM from BALB/c mice, 100 microM piriprost potassium was required to produce changes in A23187-stimulated chemoattractant and LTB4 release; of note, the generation of LTB4 in response to A23187 by BAM from aged BALB/c mice was significantly greater than that observed with cells from the younger animals under all conditions studied. Finally, with BAM from DBA/2 mice, 50 microM piriprost potassium significantly reduced chemoattractant activity in both groups of animals, but the lipoxygenase inhibitor had no effect on LTB4 production. Thus, although these studies revealed substantial age and strain-related differences in the release of neutrophil chemoattractant activity by murine BAM, they did not demonstrate deficiencies that might enhance the susceptibility of the senescent host to infection of the lower respiratory tract.