Nature of the Immune Response to Mycoplasma Pneumoniae

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Abstract
Summary: The nature of antibodies formed in the serum of rabbits and man following immunization or infection with Mycoplasma pneumoniae has been studied using serologic and immunochemical techniques. Measurement of fluorescent-stainable (FA), complement-fixing (CF), tetrazolium reduction-inhibiting (TRI) and growth-inhibiting (GI) antibodies in immunized rabbits revealed that FA and CF antibodies appeared within 10 days and remained elevated for at least 90 days. TRI and GI antibodies appeared later and accumulated slowly, reaching maximum levels only after 30 days. The immunoglobulin composition of representative M. pneumoniae-immune rabbit sera was determined by gel filtration and immunoelectrophoretic analysis. CF and GI antibodies were demonstrated in both 19S and 7S immunoglobulin fractions; 19S antibodies, present in early sera, declined as the 7S component became predominant. Cold hemagglutinating (CHA), indirect-hemagglutinating (IHA), CF and GI antibody titers in adult patients with M. pneumoniae pneumonia, followed up to 12 months, attained maximum levels sequentially. CHA peaked at 3 weeks, followed by IHA and CF at 3 to 4 weeks; GI titers peaked at 6 months. Characterization of the specific immunoglobulin composition of a series of convalescent human sera revealed the appearance of different biologic properties to be related to the relative content of IgM, IgA and IgG as a function of time. These studies provide an explanation for the differences in results obtained by various serologic methods and provide criteria by which techniques may be selected for detection of antibodies according to the time that samples are collected in relation to illness or immunization.