The Valency of Human γM Immunoglobulin Antibody

A human macroglobulin (γM) was separated from the serum of normal donors who had been immunized with typhoid vaccine. The γM antibody to Salmonella typhi O 12 antigen was obtained by chromatography of the γM-globulin on a column of specific immunoadsorbent. The somatic antigen, i.e. the lipopolysaccharide of S. typhi, was extracted from the bacterium and partially hydrolyzed. A tetrasaccharide, which is the antigenic determinant of the lipopolysaccharide, was separated by paper chromatography. Equilibrium dialysis of the purified γM antibody with the tetrasaccharide showed that the antibody had 10 antigen-combining sites per molecule and an association constant with antigen of 2.7 x 104.