Gold Cluster Compounds are Useful Immunoprobes

Immunocytochemistry generally refers to methods directed toward obtaining information on the in situ distribution of antigens in cells and tissues. Immunocytochemical methods can be applied at either the light or electron microscope levels, or both in concert. The detection of antibody recognition of an antigen (i.e., localization of an antigen) relies upon a reporter system. At the light microscope level, enzymes (e.g., horseradish peroxidase) or fluorochromes are the most widely used reporters in immunocytochemistry. At the electron microscope level, particulate probes (e.g., colloidal gold) are the most widely used reporters. However, enzymes and even fluorochromes can be used at the EM level.In this abstract, we discuss our use of gold cluster immunoprobes as the reporter system in both light and electron microscope level immuncytochemistry. These gold cluster immunoprobes, are commercially known as NanogoldTM (NG). These probes are very small with a diameter of 1.4-nm.

Enhanced Labeling Efficiency Using Ultrasmall Immunogold Probes: Immunocytochemistry

Detection of antigen-antibody interactions in immunocytochemistry relies on a reporter system. The most commonly employed reporter systems used are fluorochromes, enzymes, and particulate probes. This article considers the advantages and disadvantages associated with ultrasmall immunogold particles as the reporter system in immunocytochemical applications.

Novel labeling methods for em analysis of ultrathin cryosections

Ultrathin cryosections are the most favorable material for localization of intracellular antigens with particulate probes (e.g., colloidal gold) in post-embedding immunocytochemistry. Cryosections are prepared under the most benign conditions as compared to embedding samples in various kinds of plastic media. Typically, higher labeling efficiencies can be achieved with ultrathin frozen sections than with plastic sections.We have utilized human neutrophils, the most abundant type of leukocyte, as a model system to explore labeling procedures for ultrathin cryosections. These labeling procedures can serve as alternative or complementary approaches to the traditional colloidal gold label. Neutrophils are characterized by the presence of numerous granules in their cytoplasm. For many years, the model for neutrophil structure has held that there are two granule types in these cells, the socalled azurophilic and specific granules. We have described an additional cytoplasmic compartment with unusual properties in neutrophils. This compartment is characterized by the presence of the enzyme alkaline phosphatase (Fig. 1).