A simple two-step method for purification of secretory IgA from human colostrum.

This paper describes an extremely simple method for the purification of secretory IgA in two steps from a colostrum pool. The first step of this technique utilizes the agar transparency effect produced by high concentrations of secretory IgA contained in colostrum pool when it is subjected to electrophoresis in this support. The secretory IgA is obtained by extraction and elution of the transparent zone adjacent to the well. In the second step, in order to obtain the maximum degree of purity, the eluate is subjected to precipitation with ammonium sulfate (1.33 M) or chromatographed through Sephadex G-200 gel. The simplicity of the method and the purity of the protein obtained make this procedure suitable for purification of macromolecular substances in concentrated state.