Electron Microscopic Recognition of Surface Antigen by Direct Reaction and Ferritin Capture with Guinea Pig Hybrid Antibody

摘要

We have recently reported the results of electron microscopic studies of rabbit small intestinal mucosa in which sucrase was identified as a part of the epithelial cell surface by virtue of its reactivity with ferritin-labeled anti-enzyme (1). In the specific reaction with mucosal villi, the periphery of antibody-bound ferritin molecules was separated from the membrane by a minimal distance of 85 ?. This latter observation might be explained in part by the possibility that ferritin molecules were attached to the immunoglobulin sufficiently close to the specific combining site to causesome degree of steric hindrance and hence limit the approximation of antibody and antigen. Hybrid antibodies (anti-enzyme/anti-ferritin) first bound to the cell surface antigen might on subsequent reaction with ferritin bring the label into closer apposition with the membrane. Experiments to test this hypothesis are reported here.Materials and Methods. Immunoglobulin G was obtained from guinea pigs immunized (2) against rabbit intestinal sucrase or horse spleen ferritin.