Rabbit Gamma Globulin. Gamma globulins are purified from non-immunized animal serums by salt fractionation, ion-exchange chromatography and gel filtration. Gamma globulins are an inexpensive source of IgG with only trace amounts of other immunoglobulins and/or non-immunoglobulin serum proteins. Gamma globulins are supplied as sterile liquids in phosphate buffer without stabilizers or preservatives.