Abstract
Bovine serum albumin (BSA) embedding and ultracryomicrotomy were used to prepare thin sections of glutaraldehyde-fixed skeletal muscle; these were then treated with antibodies against alpha-actinin, myosin, and actin. Three criteria were then used to compare these two techniques: 1) The preservation of fine structure; 2) the specificity of labeling with antibodies and 3) the amount of antibody bound to a particular antigen. Fine structure was better preserved using ultracryomicrotomy. Both techniques, under optimal conditions, gave specific labeling of muscle components. The amount of antibody bound was higher for BSA sections than for frozen sections. The conclusion is that, while ultracryomicrotomy gives superior qualitative results, the most reliable quantitative estimates would be obtained by using both methods together. Ultracryomicrotomy has the additional advantage that semithin sections can be visualized by immunofluorescence.