The preparation of human intrinsic factor-cobalamin complex from human gastric juice by immunoadsorption

Abstract

1. (1) Immune complexes of human intrinsic factor were prepared by mixing gastric juice saturated with vitamin B 12, and sera from patients with pernicious anaemia that had a high proportion of binding (Type II) antibody. 2. (2) The complexes were isolated by sodium sulphate precipitation followed by Sephadex G-150 gel filtration. 3. (3) Acid conditions dissociated the immune complexes and allowed separation of specific antibody and purified antigen bound to vitamin B 12 by Sephadex G-200 gel filtration. 4. (4) Specific antibody was covalently attached to Protein A Sepharose CL-4B by coupling with water soluble carbodiimide which allowed intrinsic factor-B 12 complex to be purified directly from gastric juice. 5. (5) The intrinsic factor obtained after iodination, ran as a single band on SDS-polyacrylamide gel electrophoresis and was biologically active.