Electroimmunoassay of human immunoglobulin M of different charges

Abstract

IgM components equal in size but differing in charge ( β 2− γ 3) were isolated from macroglobulinemic sera. Electroimmunoassay of the equally concentrated IgMs (72 mg/100 ml) against anti-IgM was performed in a region where dose response curves showed the sensitivity to be appropriate. IgMs which had a higher anodal migration rate than the bulk of molecules in a standard preparation gave values which deviated +9 to 45% from the real concentration, depending on whether the mean migration rate of the ‘standard’ was the same or higher than that of the anti-IgM antibodies used. IgMs having a migration rate more similar to the mean migration of a ‘standard’, deviated −45 to 6% from the real concentration under the same circumstances, while IgMs migrating as the most cathodal molecules in a ‘standard’ gave +30 to −55%. The distribution due to charge did not seem to be the same in antibody containing medium as in pure agarose gel at the same pH. Material which on agarose gel electrophoresis seemed to contain only molecules migrating towards the cathode seemed on electroimmunoassay (at pH 8.6) also to contain material which migrated towards the anode and material which showed slightly anodal migration rate seemed also to contain molecules which migrated towards the cathode.