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.

Morfološke i funkcionalne karakteristike makrofaga izolovanih iz različitih organa: kostne srži, slezine, peritonealne šupljine i alveola ispitivane su pre i posle aktivacije u in vitro uslovima. Da bi se ispitale karakteristike makrofaga koji se nalaze u ispitivanim tkivima analizirane su adherentne ćelije dobijene nakon inkubacije od 24 časa. Uticaj aktivacije makrofaga na njihovu morfologiju i funkciju (ekspresiju Fc receptora, sposobnost fagocitoze čestica kvasca i sadržaj enzima nespecifične esteraze) ispitivan je nakon kultivisanja adherentnih ćelija u toku 8 dana. Morfološkom analizom utvrđeno je značajno povećanje veličine alveolarnih makrofaga kultivisanih tokom 8 dana u prisustvu faktora koji stimulišu rast kolonija i limfokina. Pokazano je da adherentne ćelije iz različitih tkiva izolovane nakon 24 sata i 8 dana imaju slične funkcionalne karakteristike. Više od 90% tih ćelija je eksprimiralo Fc receptore, imalo sposobnost fagocitoze i sadržavalo nespecifičnu esterazu. Međutim, u populaciji alveolarnih makrofaga, pre kao i nakon in vitro aktivacije, utvđeno je prisustvo ćelija koje su sadržavale nespecifičnu esterazu u citoplazmi, ali nisu eksprimirale Fc receptore, niti su imale sposobnost fagocitoze. Ovi rezultati potvrđuju da su karakteristike alveolarnih makrofaga u odnosu na makrofage iz drugih tkiva zavisne od njihovog mikrookruženja.