SCANNING ELECTRON MICROSCOPIC STUDY OF THE COMPLEMENT RECEPTOR SITE ON HUMAN DIPLOID FIBROBLASTS.
Sheep red cells, treated with 19S antibody and mouse serum as the source of complement (EAC), interact with human diploid fibroblasts and the immune adherence occurs owing to the existence of the complement receptor site on the cell membrane of human fibroblasts. Examined under a scanning electron microscope, EAC attach only to the microvilli of fibroblasts, and at that time many microvilli with free end can be observed on the cell membrane of fibroblasts. On the contrary the cell surface of normal fibroblasts, which have not incubated with EAC, seems to be relative smooth and microvilli are not so prominent. It might be speculated that fibroblasts posess the complement receptor site on the top of microvilli, and the microvilli become prominent when the cell membrane is activated with some stimuli.