Specificity testing of ab39418. BOSC cells were transiently transfected with an expression vector encoding either the extracellular domain of IL-13Rα1 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 IL-13Rα1 (red curve) and the irrelevant protein trans-fectants (green curve). A posi-tive signal was obtained only with IL-13Rα1 transfected cells.