Colloidal gold as a marker for the light microscope detection of leukocyte cell surface antigens with monoclonal antibodies.

Colloidal gold was used as a marker for the light microscopic detection of leukocyte cell surface antigens with monoclonal antibodies. Leukocytes were first incubated with monoclonal mouse antibodies, and then with colloidal gold-labeled goat-anti-mouse antibodies. The cells were fixed and stable preparations were made. Positive cells displayed numerous dark granules all over their surface membrane. In electron microscopy, these granules appeared as patches of gold particles. This immunogold staining method proved to be a reliable tool for the enumeration of T-lymphocytes and their subclasses. Accurate cell recognition, based on morphology and cytochemistry, permitted rapid cell counting. The procedure was also applied on small volumes of whole blood. This approach was used as a microtechnique for the enumeration of lymphocyte subpopulations in pediatric patients. In normal peripheral blood, the intracellular enzymatic activities of the immunogold-labeled lymphocytes were detected by the classical cytochemical reactions. The staining patterns for acid alpha-naphthyl acetate esterase, acid phosphatase and beta-glucuronidase were identical to those found in smears of unlabeled cells. The cytochemical profile of the OKT-defined normal lymphocyte subpopulations was established.