Dissociation of aggregated IgG and denaturation of monomeric IgG by acid treatment.
Conditions for obtaining a large quantity of monomeric IgG which can be used for intravenous injections in humans was successfully established with human serum IgG preparation obtained using the ethanol fractionation method. When dissociation of IgG aggregates and denaturation of IgG monomers contained in the starting material were examined at various pH values, the treatment for 60 min at 28 degrees C at pH 3.8-4.0 was found to be optimum for obtaining such monomeric IgG. At this pH range, the dissociation of IgG aggregates into monomeric IgG reached maximum, without producing polymeric IgG. When monomeric IgG was treated at this acidic pH condition, its biological and physicochemical properties such as acid difference spectrum, molecular weight, plasmic digestion ratio, and complement-, antigen- and protein A-binding activities remained unchanged. The fact that large scale production of monomeric IgG can be easily performed under such conditions is discussed.
D000937:Antigen-Antibody Reactions; D002384:Catalysis; D003165:Complement System Proteins; D005341:Fibrinolysin; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007074:Immunoglobulin G; D008970:Molecular Weight; D011485:Protein Binding; D011489:Protein Denaturation; D013205:Staphylococcal Protein A
D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; D003165:Complement System Proteins; D005341:Fibrinolysin