Comparison of certain properties of naturally occurring low molecular weight Gamma M and the Gamma M monomer derived by reduction and alkylation of 19S Gamma M.

Abstract

Summary A naturally occurring low molecular weight γM protein (γM N ) was isolated from the serum of a patient with type I dysgammaglobulinemia by preparative electrophoresis and gel filtration. This protein was compared to the macroglobulin (γM 19 ) isolated from the patient9s serum and to the γM subunit (γM S ) prepared by reduction and alkylation of γM 19 . The results indicate that γM N and γM S are similar in size and have the same antigenic determinants. These observations support the concept that the γM N is a naturally occurring subunit of γM 19 and is very similar to γM S , γM 19 , γM N and γM S were also prepared from the patient9s serum after tetanus immunization and were found to bind radiolabeled tetanus toxoid. Most, but not all, controls did not show nonspecific binding of tetanus toxoid. These results suggest but do not conclusively establish the capacity of these γM proteins to bind antigen specifically.