Commercial preparations of colloidal gold-antibody complexes frequently contain free active antibody.
Using a simple fluorescence test, we show that commercially prepared colloidal gold complexes with goat second antibodies often contain free active antibody. Because such antibodies will compete with antibody-colloidal gold particles for antigen binding sites, labeling intensity at the ultrastructural level must necessarily be submaximal to an unknown degree with such preparations. A survey of five preparations suggests that the problem may be widespread. We recommend that a test of the sort described be incorporated routinely into protocols with all colloidal gold products.
Kramarcy
N R
NR
Department of Physiology, University of North Carolina, Chapel Hill 27599.
Sealock
R
R
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D000888:Antibodies, Anti-Idiotypic; D003102:Colloids; D005455:Fluorescent Antibody Technique; D006046:Gold; D007074:Immunoglobulin G / Q000032:analysis; D007150:Immunohistochemistry / Q000592:standards; D007202:Indicators and Reagents / Q000592:standards*; D051379:Mice; D051381:Rats
D000906:Antibodies; D000888:Antibodies, Anti-Idiotypic; D003102:Colloids; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D006046:Gold