[Interaction of antibodies of different immunoglobulin classes with specific O-antigens and Salmonella haptens]

A study was made of the neutralizing properties of antisalmonella antibodies belonging to different immunoglobulin classes in respect to specific O-antigen (Lipopolysaccharide S. anatum) and haptens of salmonellae. In comparison with IgM-antibodies, IgG-antibodies were more stable bound not only with the univalent trisaccharide determinant, but also with the polysaccharide. However, in regard to the lipopolysaccharide complex the neutralizing activity of IgM- and IgG-antibodies was about the same; IgA-antibodies possessed the greatest neutralizing activity with respect to all the antigenic preparations used. The minimal neutralizing dose of the antigen and haptens increased with the reduction of the size of their molecule. A marked heterogeneity of antibodies of each of the immunoglobulin classes by their antigen-neutralizing properties was revealed in individual sera.