Expression of AC133 on retinoblastoma cell lines. (A) FACS analysis of Y79 and WERI-Rb-1 cell lines stained with AC133-PE: A, isotype control; B, Y79 cells; C, PMA-activated Y79 cells; D, WERI-Rb-1 cells. (B) Immunoprecipitation of AC133 antigen from PMA-activated Y79 and WERI-Rb-1 cells. Lanes 1 to 4, PMA-activated Y79 cells immunoprecipitated with 2.5, 5, 10, and 20 μg AC133, respectively. Lanes 6 to 9, WERI-Rb-1 cells immunoprecipitated with 2.5, 5, 10, and 20 μg AC133. Lanes 5 and 10, molecular weight markers.