CF™ dye goat anti-mouse IgG isotype-specific secondary antibody conjugates are labeled with our exceptionally bright, photostable CF™ dyes. The conjugates are prepared from affinity-purified antibodies that react with Fc portion of the heavy chain of mouse IgG1, IgG2a, or IgG2b. To minimize cross reactivity, the antibodies are cross-adsorbed against other mouse IgG subclasses (IgG2a, IgG2b, IgG3), and human, bovine and rabbit serum proteins. Near-infrared fluorescent CF™770 has excitation/emission maxima at 770/797 nm, and produces exceptionally bright and photostable antibody conjugates. CF™770 is compatible with near-infrared imaging systems.