VISUALIZATION OF SILVER-ENHANCED REACTION-PRODUCTS FROM PROTEIN AND IMMUNO-COLLOIDAL GOLD PROBES BY LASER-SCANNING CONFOCAL MICROSCOPY IN REFLECTION MODE

We have employed a laser scanning confocal microscope in reflection mo de to directly and indirectly visualize sites of deposition of silver- enhanced reaction products from colloidal gold probes. A direct approa ch was used for the localization of alpha-fetoprotein receptors in hum an myoblasts by incubating primary cultures with an alpha-fetoprotein- goId conjugate. For an indirect approach, cultured CEM cells, derived from a human T-lymphoma cell line, were incubated with a mouse monoclo nal antibody to mature T-cells, followed by a gold-labelled antibody t o mouse immunoglobulins. Multiple optical sections of each sample were collected by reflection laser scanning confocal microscopy and combin ed into three-dimensional renderings. A (non-confocal) transmission im age was generated of each field for comparative purposes. The increasi ng use of reflection laser scanning confocal microscopy combined with colloidal gold conjugates as biological markers will probably be of co nsiderable advantage in cytochemical analysis.