Analysis of Fcγ receptors on human peripheral blood leukocytes by flow microfluorometry. I. Receptor distributions on monocytes,Tγ cells and cells labeled with the 3A1 anti-T cell monoclonal antibody

A dual parameter flow microfluorometric technique for accurately measuring Fcγ receptor (FcR) expression on defined subsets of cells within a heterogeneous cell sample was developed. The FcR distribution of human peripheral blood mononuclear cells consists of three distinct peaks. By analyzing cells fluorescently labeled with the 3A1, an anti-T cell hybridoma antibody (using a green-emitting fluorophore) and for FcR (with a red-emitting fluorophore), and by using cell isolation procedures, it was shown that the cells lying within the peak with intermediate FcR density are mainly monocytes, while cells lying within the peaks with highest and lowest (i.e. negative) FcR densities are predominantly T cells. The FcR⁺ T cells (T_γ cells) express higher levels of the 3A1 antigen than other T cells, thus demonstrating the utility of the 3A1 hybridoma antibody as a marker for T_γ cells.