Whole IgG antibodies are isolated as intact molecules from antisera by immunoaffinity chromatography. They have an Fc portion and two antigen binding Fab portions joined together by disulfide bonds and therefore they are divalent. The average molecular weight is reported to be about 160 kDa. The whole IgG form of antibodies is suitable for the majority of immunodetection procedures and is the most cost effective.Based on immunoelectrophoresis and/or ELISA, the antibody reacts with the F(ab')2/Fab portion of cat IgG.  It also reacts with the light chains of other cat immunoglobulins.  No antibody was detected against the Fc portion of cat IgG or against non-immunoglobulin serum proteins.  The antibody may cross-react with immunogloublins from other species.