Purification of Human IgA

Abstract This unit describes the purification of human immunoglobulin A (IgA).The main method utilizes an IgA‐binding protein (IgA‐bp) as an affinity reagent, similar to the IgG‐binding proteins, protein A and protein G. An alternate protocol describes a method for isolating IgA1 using affinity column chromatography with Jacalin, an IgA1‐specific lectin. Another alternate protocol describes IgA purification by conventional fractionation using size‐exclusion chromatography.