Direct immunogold staining technique based on monoclonal antibodies: an immediate approach to the immunostaining of lymphocytes.

The report provides a procedure for labelling of monoclonal antibodies (moab's) with colloidal gold particles (mean diameter 30 or 40 nm). This procedure was exemplified for the moab's BL-T2, BL-Ig-L/1, and BL-Ia/1, which label mature T (and some populations of B) lymphocytes, B lymphocytes, and HLA class II antigen bearing lymphocytes, respectively. Each moab was characterized by an individual pH optimum for stabilization of the gold sol. The pH optima were +/- 5 (BL-T2), +/- 7 (BL-Ia/1), and +/- 9 (BL-Ig-L/1). The immunogold staining reagents were used for a direct immunostaining protocol of lymphocytes, which needs less than 100 min. The intensity of this direct immunolabelling was comparable with this one resulting from the indirect IGS. Furthermore, the comparison of the direct IGS with the immunofluorescence technique does not revealed any significant difference in the mean cell counts. The presented immunolabelling method offers a straight cell tagging, which can be advantageously used for a double staining procedure.