Immune Response in Mycoplasma Pneumoniae Infection 339

Several investigators have demonstrated a sequential synthesis of 19 S and 7 S antibodies upon antigenic stimulation; commonly there is a transient early 19 S response followed subsequently by 7 S production (1-6). The nature of the antigen, however, can influence the kinetics of the 19 S and 7 S antibody response. Thus, certain polysaccharide antigens are known to induce a long lasting 19 S antibody synthesis (1, 7). Viral antigens have been found to induce complement~fixing (CF) antibodies almost exclusively of the 7 S class (4-6) whereas CF antibodies to bacteria, rickettsiae and Toxoplasma may be both 19 S and 7 S (8-11). 19 S and 7 S antibodies also may show different efficiencies in various serologic tests (12). Comparatively little is known about the physicochemieal properties of antibodies formed in response to mycoplasma infections. Cold agglutinins which often appear in Mycoplasma pneumoniae infections belong to the 19 S globulins (13). I t was reported previously that CF and indireet-hemagglutinating (IHA) antibodies to M. pneumoniae can be both of the 19 S and the 7 S type (14). CF antibodies to M. pneumoniae of both molecular types also have been demonstrated by Sehmidt et al. (15). The present article correlates the distribution of M. pneumoniae antibodies within the 19 S and 7 S class of immunoglobulins with the time after infection. An account of part of this work was given at the Fifteenth Scandinavian Congress of Pathology and Microbiology, Copenhagen, June 1967 (16).