Autologous T cell–sAg–pulsed CLL B cell conjugates from untreated (UT) or lenalidomide-treated (Lenalid.) CLL patient (A) or Eμ-TCL1 mouse cells (B) were selected at random for imaging and scored for accumulation of F-actin (red) at the immune synapse. As controls (healthy), autologous age-matched healthy donor or wild-type mice cells were used. Data are the mean ± SD from 3 independent experiments, with 50 conjugates analyzed per experiment. The confocal images shown are CD4⁺ human T cells. (C) Autologous T cell–sAg–pulsed CLL B cell conjugates from untreated CLL or lenalidomide-treated Eμ-TCL1 mouse cells were scored by visual counting using a confocal microscope. As controls, age-matched wild-type mice cells were used. Data are the mean ± SD from 3 independent experiments, with 50 random T cells analyzed per experiment. (D) Autologous T cell–sAg–pulsed CLL B cell (blue) conjugates from untreated or lenalidomide-treated patient CLL B and CLL T cells were stained for phosphotyrosine (green) and F-actin (red) using immunofluorescence and confocal microscopy. Images shown are representative of evaluation of 150 conjugates from 3 independent experiments. Arrows indicate protein localization at the T cell–APC synapse site. (E) Autologous cytotoxicity of CLL B cells was compared between untreated and lenalidomide-treated patient CLL B and CLL CD8⁺ T cells. Killing was assessed at the effector/target ratios shown. Data are mean ± SD from 6 independent CLL patient experiments. Autologous healthy donor cells were used as controls (with or without sAg-pulsed B cells). Original magnification, ×63.