Specificity testing of ab39418. BOSC cells were transiently transfected with an expression vector encoding either the extracellular domain of IL13Rα1 or an irrelevant protein. Expression of the constructs was tested with an anti-tag monoclonal antibody (B, green curves), an irrelevant monoclonal antibody served as negative control (bluecurves). For specificity testing (A), purified ab39418 was tested on both the IL13Rα1 (red curve) and the irrelevant protein trans-fectants (green curve). A posi-tive signal was obtained only with IL13Rα1 transfected cells.