Endocytosis and intracellular transport of colloidal gold-labeled ConA in mouse peritoneal macrophage

Abstract

The purpose of this study is to investigate the endocytosis and intracellular transport of colloidal gold-labeled ConA (CG-ConA) in mouse peritoneal macrophages using pre-embedding staining method.Labeling with CG-ConA, acid phosphotase (AcPase) cytochemistry and electron microscope (EM). Mouse peritoneal macrophages were elicited by intraperitoneal injection of glycogen, after which 1ml CG-ConA (CG 1mg/ml) was injected per mouse. At different intervals after injection of CG-ConA (5,10,20 and 30 min), the peritoneal macrophages were isolated and treated for their AcPase activity according to the produce of Gomori. The CG-ConA and AcPase activity in these macrophages were examined under TEM.Surface distribution of CG-ConA 5-1Omin after intraperitoneal injection of CG-ConA many clusters and clumps of CG-ConA particles were formed on the macrophages (Fig. 1). The cluster formation is temperature-dependent and receptor-mediated, because the same phenomenon could be observed in the elicited macrophages after incubation with CG-ConA at 37°C in vitro, but not in those at 0-4°C and those incubated with pure CG particles. At 0-4°C CG-ConA particles were randomly and diffusely distributed over the cell surface. Aggregates of CG-ConA particles were often found between cellular processes.