[Phagocytosis mechanisms of alveolar macrophages and granulocytes (author's transl)]

Alveolar macrophages and granulocytes protect the organism against invaded microorganisms under various conditions. To investigate whether the environmental difference may influence the various phagocytic functions the adherence, chemotaxis, ingestion rate, degranulation as well as the bactericidal activity were determined in alveolar macrophages and granulocytes obtained from guinea pigs. In addition, the cytoskeleton was examined by observing the fluorescence of Concanavalin A receptors. Various functional differences between both cell types have been demonstrated. Both cell types exhibited the same adherence. In contrast, granulocytes demonstrated a greater chemotactic activity and ingestion rate than alveolar macrophages. Following the exposure to opsonized zymosan alveolar macrogphages secreted almost totally the lysosomal enzyme beta-glucuronidase during the degranulation. Nevertheless, alveolar macrophages exhibited a lower bactericidal activity than granulocytes. This functional differences were not caused by an alteration of the cytoskeleton. A random fluorescence distribution of FITC-Concanavalin A receptors was observed in 72% alveolar macrophages and 73% granulocytes, demonstrating polymerisation of the microtubuli. Only 12% alveolar macrophages and 11% granulocytes showed a capped FITC-Concanavalin A fluorescence which is associated with an alteration of the microtubulin. This study demonstrates that the difference in adherence, chemotaxis, ingestion rate, as well as the bactericidal activity of alveolar macrophages and granulocytes is a specific cell-type property.