Validation of specificity of the custom NRG1 Type III antibody. (A): Comparison of NRG1 Type III detection using the custom N-terminal NRG1 Type III polyclonal antibody (left) and a commercial C-terminal NRG1 Type III polyclonal antibody (SMDF, right). (B-D) Demonstration of the specificity of the N-terminal NRG1 Type III polyclonal antibody. The indicated amounts of the N-terminal NRG1 Type III antibody (B), a polyclonal antibody against NRG1 Type I (C) or the C-terminal NRG1 Type III antibody (SMDF, D) were preabsorbed with the immunizing peptide in a 1:50 to 1:200 ratio for 1 hr at 25°C and then used for immunoblot analysis of a sciatic nerve sample. The peptide specifically decreased the detection of the 75 kDa NRG1 Type III band but had no effect on detecting NRG1 Type I or the 65 kDa C-terminal NRG1 Type III fragment.