Divergent results in radial immunodiffusion with antisera differing in precipitation properties with respect to individual immunoglobulin subclass. II. The antiserum factor.

Differences in the antibody composition of antisera influence results obtained by radial immunodiffusion. If more than one subclass of the same immunoglobulin class is present in an antigen mixture, the occurrence of one or more subclass specific antibody species in antisera used for radial immunodiffusion leads to the production of precipitation rings smaller than rings produced by comparable antisera without subclass activity. The presence of antibodies against common immunoglobulin determinants only leads to production of larger precipitation areas. If one or more subclass specific antibody species are present in the antiserum this may further lead to production of double precipitation rings in radial immunodiffusion, depending on the subclass ratio in the antigen mixture. The production of antisera suitable for radial immunodiffusion is discussed.