The effect of processing methods on intravenous immune globulin preparations

In this comparative study we investigated five commercially available immunoglobulin preparations manufactured by various processing methods. Two enzyme-modified preparations and one chemically modified preparation demonstrated appreciable variation in molecular weight species when compared with native preparations utilizing gentle processing conditions. One native preparation, processed with DEAE Sephadex, was low in IgG4 subclass, while the enzymic and chemical processing methods provided products demonstrating substantial variation in subclass distribution. The other native preparation, formulated at low pH, demonstrated particularly low turbidity values, indicating greater IgG stability at pH 4.25 than at pH 7.0. Certain antibody levels were seen to be greatly reduced in the modified preparations. These differences are discussed with reference to effects of the processing conditions employed.