Homogenous IgA Monomers, Dimers, Trimers and Tetramers from the Same IgA Myeloma Serum

Starting from two IgA1 myeloma sera, the isolation of monoclonal monomeric, dimeric, trimeric and tetrameric IgA in a high state of purity and size homogeneity for each serum is described. The method combined repetitive gelfiltrations on Ultrogel AcA22 with affinity chromatography on Jacalin-Sepharose. These various forms of pure polymeric IgA obtained from the same monoclonal IgA should allow a precise comparison of their respective structure and reactivity with different IgA-binding proteins, such as IgA Fc-receptors, the polymeric Ig receptor, and lectins.