FIG. 2.
Analysis of IL-16 protein expression. (A) EREB2.5 cells were starved of estrogen for 5 days and were then either left unstimulated (−) or were activated by the addition of estrogen (+) for the times indicated. RIPA extracts were prepared, and 50 μg of protein was analyzed by SDS-PAGE (lanes 1 to 11). Then, 10 ng of human recombinant IL-16 was included to ensure detection of the 20-kDa mature secreted form of IL-16 (lane 12). Primary B cells were isolated by CD19-positive selection and either left uninfected, infected with EBV, or stimulated with PMA for 48 h (lanes 13 to 16). Then, 50 μg of protein extract was analyzed for the presence of IL-16 with the mouse monoclonal antibody 14.1. (B) The membrane was reprobed for the expression of the 20-kDa cleaved active form of caspase 3.