Applications of immunogold labeling in ultrastructural pathology

This review provides an update on the use of postembedding immunogold labeling, preferentially of the protein A-gold technique, for electron microscopic research in diseased states. In the first part, some helpful antigen recovery techniques for use of immunogold labeling of ultrathin sections prepared from routinely aldehyde (and osmium tetroxide) fixed and conventionally epoxy resin-embedded tissue are cited. In the second part, selected applications for studies of tumor cell surface conjugates, such as polysialic acid in Wilms tumor, proinsulin-insulin conversion in human insulinoma, and the importance of pre-Golgi intermediates for retention of a misfolded polypeptide hormone in a protein misfolding disease, are discussed.