Properties of tissue specific macrophages before and after in vitro activation

Abstract

Macrophages derived from different tissues: bone marrow, spleen, peritoneal cavity and alveolus, were examined from the aspects of their morphology and functional characteristics expression of Fc receptors (FcR), phagocytic activity towards yeast particles and nonspecific esterase (NSE) content¹ before and after in vitro activation. Twenty four-hour-adherent cells were isolated with the aim of analyzing the characteristics of resident tissue macrophages. Following cultivation in vitro 8-day-adherent cells were used to investigate the influence of macrophage activation on their morphology and function. Morphological analysis of cell smears, performed in respect to cell size, showed significant enlargement, especially in the population of alveolar cells cultured for 8 days and activated with colony-stimulating factors (CSFs) and lymphokines. It was also demonstrated that 24-hour- and 8-dayadherent macrophages derived from different tissues exhibited similar properties. All these cells were more than 90% FcR-positive (FcR+) NSE-positive (NSE+) and had phagocytic properties. However, within the population of alveolar macrophages there were some NSE+ cells lacking FcR and phagocytic activity, even after in vitro activation. These results confirmed that the properties of alveolar macrophages differing from those of macrophages from other tissues were dependent on their microenvironment.