HRP-conjugated goat anti-mouse IgG secondary antibody is affinity-purified and is suitable for detecting mouse primary antibodies used in WB, IHC and ELISA. First, a primary antibody of mouse origin is bound to a target antigen. Following a brief wash, HRP-conjugated goat antimouse secondary antibody is applied to form a complex with the primary antibody. After another brief wash, HRP substrates such as luminol or 3,3'-diaminobenzidine (DAB) are added to produce detectable chemiluminescence or insoluble colors.