Comparisons of alveolar and peritoneal macrophages: soluble protein, esterase, dipeptidyl aminopeptidase II, and proteinase inhibitor.

The content of soluble protein, nonspecific esterase, dipeptidyl aminopeptidase II (DAP II), and proteinase inhibitors was compared for alveolar (AM) and peritoneal (PM) wash cells of rats. The cells present in the wash fluids were 85-90% macrophages in the peritoneal wash and 95% in the alveolar wash. Macromolecular components were resolved from whole cell homogenates by polyacrylamide gel isoelectric focusing (PAGIF) on horizontal gels and were identified cytochemically. Banding patterns clearly indicated a larger number of esterase zones in peritoneal compared to alveolar macrophages and ten previously unrecognized isozymes of DAP II in peritoneal macrophages with only three evident in their alveolar counterparts. (On whole blood smears, these cytochemically demonstratable enzymes were limited to macrophages, although DAP II was seen also in some mast cell granules). A protein band similar to the M6 band of alpha-1-antitrypsin in human serum was seen both in alveolar and peritoneal wash preparations. In addition, nine other major trypsin-binding protein bands were observed in the peritoneal macrophages, including two bands not observed in the alveolar macrophage extracts.