Distribution of Antibodies Within 19 S and 7 S Immunoglobulins Following Infection with Mycoplasma Pneumoniae

Abstract

Sera from cases of pneumonia with serologic evidence of Mycoplasma pneumoniae infection were fractionated by sucrose gradient centrifugation and gel filtration. The distribution of complement-fixing (CF), indirect hemagglutinating (IHA) and tetrazolium reduction-inhibiting (TRI) antibodies within the 19 S and 7 S immunoglobulins was determined at different times after onset of illness. The proportion of 19 S to 7 S antibodies varied considerably between individuals even when compared at the same time after clinical onset. However, in the majority of cases there was an increase of 7 S relative to 19 S CF antibodies with time after onset. Yet, most cases still had some 19 S CF antibodies after 5 to 12 months. TRI antibodies also showed a temporal shift in their distribution between 19 S and 7 S globulins. IHA antibodies were predominantly 19 S globulins. In half of the cases studied there was an increase of 7 S relative to 19 S IHA antibodies with time after infection while the remaining cases showed 19 S IHA antibodies exclusively even after 5 to 12 months. In some cases both CF and IHA antibodies showed a partial temporal shift from 19 S to 7 S immunoglobulins whereas in other cases this trend was noted with only one of the antibodies. No difference was found in the CF antigen requirement of sera collected in the early and late phase of infection or between 19 S and 7 S antibodies.