Pre-embedding immunohistochemistry as an approach to high resolution antigen localization at the light microscopic level.

Pre-embedding immunohistochemistry with subsequent embedding in hydroxypropyl methacrylate enables one to obtain high resolution staining of antigens in 1 mu tissue sections. A routine method using formaldehyde fixation, methanol permeation, and an indirect method with fluorescein-labeled second antibody is described. This method is compared with other pre-embedding staining procedures. To illustrate the method the mouse small intestine was chosen as a model and stained with antibodies to tubulin, actin, and fibronectin. Some anticipated and some unusual staining patterns were found.