Direct visualization of colloidal gold-bound molecules and a cell-surface receptor by ultrahigh-resolution scanning electron microscopy.
The structure of protein A-coated colloidal gold particles, and of macrophage cell-surface receptors conjugated with immunogold particles, was studied using an ultrahigh-resolution scanning electron microscope. Protein A, when conjugated with 15-nm gold, formed a coat completely surrounding the particle. Particles conjugated with both protein A and immunoglobulin G (IgG) were similar, but with additional protrusions formed by the IgG. IgG molecules directly bound to gold were resolved sometimes as complexes of three units, sometimes as more filamentous, V-shaped structures. On the cell surface of macrophage reacted with a monoclonal antibody to Mac-1 antigen (the murine C3bi receptor) followed by protein A-gold, gold particles were seen to be linked via the IgG to the receptor, visualized as a round granule.
Tanaka
K
K
Department of Anatomy, Tottori University School of Medicine, Yonago, Japan.
Mitsushima
A
A
Yamagata
N
N
Kashima
Y
Y
Takayama
H
H
D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000648:ultrastructure; D006046:Gold; D007074:Immunoglobulin G; D016177:Macrophage-1 Antigen / Q000648:ultrastructure; D008264:Macrophages / Q000276:immunology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D013205:Staphylococcal Protein A
D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D016177:Macrophage-1 Antigen; D013205:Staphylococcal Protein A; D006046:Gold