RESUMO
BACKGROUND/AIM: Serum-derived macrophage activating factor (serum-MAF) can rapidly activate macrophage phagocytic activity by inducing characteristic membrane ruffles designated as Frill-like structures. Serum-MAF contains γ-globulin, an activator of phagocytosis. This study examined whether serum-MAF and γ-globulin activate macrophages similarly. MATERIALS AND METHODS: Morphological changes in macrophages were observed by time-lapse imaging and the efficiency of engulfment was analysed quantitatively. Immunological staining of talin-1 and a calpain inhibitor were performed. RESULTS: The engulfment efficiency of serum-MAF- and γ-globulin-activated macrophages was significantly different. Talin-1 showed weak co-localisation with the Frill-like structures. Treatment with a calpain inhibitor similarly down-regulated phagocytosis irrespective of the activation factor. CONCLUSION: There was a difference between macrophage activation mechanisms by γ-globulin and serum-MAF. Talin may slightly contribute to serum-MAF activation. It is possible to distinguish between the calpain-dependent fundamental 'mechanism of phagocytosis' and the activating factor-dependent rapid 'activation mechanism'.
Assuntos
Ativação de Macrófagos/efeitos dos fármacos , Fatores Ativadores de Macrófagos/farmacologia , Macrófagos/efeitos dos fármacos , gama-Globulinas/farmacologia , Calpaína/farmacologia , Linhagem Celular , Regulação para Baixo/efeitos dos fármacos , Humanos , Fagocitose/efeitos dos fármacos , Células THP-1RESUMO
BACKGROUND/AIM: Serum-derived macrophage activating factor, serum-MAF, is known to increase the phagocytic activity of macrophages by enhancing the engulfment efficiency. To elucidate the mechanisms underlying phagocytic activation, morphological changes were observed and analyzed. MATERIALS AND METHODS: Morphological changes in macrophages were observed and quantitatively analyzed using scanning electron microscope (SEM) and confocal microscope. RESULTS: SEM and confocal microscopy images revealed frill-like structures and active actin accumulations, respectively, in serum-MAF treated macrophages. Actin accumulation was induced within 5 min following serum-MAF treatment. CONCLUSION: Serum-MAF induced a rapid rearrangement of cytoskeletal actin and enhanced phagocytic activity. Findings of the current study may contribute to the development of techniques that facilitate activation of the human immune system, which in turn may be beneficial for cancer immunotherapy.
Assuntos
Actinas/química , Macrófagos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-maf/farmacologia , Actinas/ultraestrutura , Humanos , Imunoterapia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Microscopia Confocal , Microscopia Eletrônica de Varredura , Proteínas Proto-Oncogênicas c-maf/genética , Células U937 , Proteína de Ligação a Vitamina D/química , Proteína de Ligação a Vitamina D/metabolismoRESUMO
BACKGROUND/AIM: Serum-derived macrophage activating factor (serum MAF) is known to increase the phagocytic activity of macrophages and potentially plays a role in activating cancer immunity. In order to reveal the contributing factors for phagocytic activation, the migratory activity and the efficiency of engulfment was analyzed. MATERIALS AND METHODS: THP-1 macrophages were induced by 12-O-tetradecanoyl-13-acetate (TPA). The migratory activity and efficiency of engulfment were analyzed by time-lapse imaging and suspension assay, respectively. RESULTS: While the distance of migration did not change before and after activation with serum MAF, the efficiency of beads internalisation was significantly increased. CONCLUSION: Phagocytic activation of serum-MAF-treated macrophages was caused by increasing the efficiency of engulfment. This study contributes to the knowledge about the activation of the immune system through phagocytic activation of macrophages.