Preparation of anti-M and -N antibodies by use of dextran gel as an immunoadsorbent.

Anti-M and -N antibodies are usually prepared from rabbit immunized with human O.M or O.N red cells. The crude antisera must be adsorbed with non-corresponding red cells to remove heteroagglutinin. To specify the crude antisera, we have employed dextran gel (DEAE-Sephadex A-50) as an immunoadsorbent, which was mixed with M or N group substance prepared by the phenol-saline method, and was fixed with formaldehyde. The substance-coupled gel was added to the corresponding crude antiserum and washed with cold saline. Then, the gel added with an equal volume of saline was heated at 55 degrees C for 10 min and applied on a funnel with slight evacuating. By this method, specific anti-M and -N antibodies (titer 1:16 to 1:32) were prepared, but the antibody was not eluted from the gel reacted with IgM fraction. The recovery rate and specificity of the eluted antibodies are discussed.