Goats were immunized with highly purified mouse IgG2a and the resulting antiserum was collected. Antibody was solid phase adsorbed using mouse IgG1, IgG2b and IgG3 immunosorbents to remove cross reactive antibody. Specific antibody was immunoaffinity purified off a mouse IgG2a containing immunosorbent. Antibody concentration was determined using an absorbance at 280 nm: 1.4 equals 1.0 mg of IgG. This antibody will react with mouse IgG2a as determined by ELISA and IEP techniques and has less than 1% cross reactivity with mouse IgG1, IgG2b and IgG3. It is suitable for blotting, ELISA and IHC applications. This antibody may cross react with IgG from other species. Optimal working dilutions should be determined experimentally by the investigator.