CXCR4 (extracellular) Blocking Peptide (#BLP-CR014) is the original antigen used for immunization during Anti-CXCR4 (extracellular) Antibody (#ACR-014) generation. The blocking peptide binds and ‘blocks’ Anti-CXCR4 (extracellular) primary antibody, this makes it a good negative reagent control to help confirm antibody specificity in western blot and immunohistochemistry applications. This control is also often called a pre-adsorption control.