TdT assay of 3DO-fixed cells after 20 hours of in vitro culture in 96-well plates with medium alone, coated with anti-CD3 (1 μg/well) and/or anti-CD2 MoAbs (5 or 1 μg/well). The numbers above the histograms indicate the percentage of apoptosis in a representative experiment. Also shown is the relative fluorescence intensity versus cell number.