Lenalidomide down-regulates tumor-inhibitory ligand expression and prevents tumor-induced lytic synapse dysfunction. (A,C) Healthy donor allogeneic T-cell synapse function with third-party healthy donor allogeneic B cells (+sAg) as APCs after primary coculture with primary CLL cells (A) primary FL and DLBCL cells (autologous patient peripheral blood T cells; C), MM cell line RPMI8226, SCC cell line VB6, OC cell line SKOV3 or nonmalignant IOSE cell line treated with neutralizing Abs (n-mAbs, α) and/or lenalidomide (1μM). Mean F-actin synapse area ± SD from 6 donor functional screens. MFI expression data (mean ± SEM from 6 independent experiments) before and after 24 hours of exposure to lenalidomide is also shown. (B) FACs MFI or percent positive expression of CD200, CD274, CD276, and CD270 on CD19⁺ CLL cells or age-matched CD19⁺ healthy donor B cells before (baseline) and after coculture (48 hours) with third-party healthy donor allogeneic T cells in the presence of vehicle control or lenalidomide (1μM). Columns show the mean plusmn] SEM from 6 coculture experiments. (D) Healthy donor CTL killing function using third-party healthy donor allogeneic B cells (+sAg) as APCs after primary coculture (48 hours) with CLL cells or age-matched CD19⁺ healthy donor allogeneic B cells. Mean percent cytotoxicity of each treatment ± SD from 6 CLL patient functional screens is shown. (E) Mean CD8⁺ T-cell synapse area and percent cytotoxicity ± SD from 6 CLL patient autologous functional screens using CLL cells pulsed with sAg as APCs. Autologous T cell–CLL(+sAg) conjugates or CTL cells alone without primary coculture were included as controls (white columns). *P < .05. The confocal images show T-cell/APC conjugate populations after primary coculture. Original magnification, 63×.