The Alexa Fluor® 633 goat anti-mouse IgG_2b is labeled with our bright far-red-fluorescent Alexa Fluor® 633 dye and is prepared from affinity-purified antibodies that react with the Fc portion of the heavy chain of mouse IgG_2b. To minimize crossreactivity, the antibody has been adsorbed against mouse IgM, mouse IgA, pooled human sera, purified human paraproteins and mouse isotypes IgG₁, IgG_2a and IgG₃ prior to labeling. Fluorescence of this long-wavelength Alexa Fluor® dye is not visible to the human eye but is readily detected by most imaging systems.