Determination of IgG, IgM, and IgA antibodies to Mycoplasma pneumoniae by an indirect staphylococcal radioimmunoassy.

An indirect staphylococcal radioimmunoassay (SRIA) has been developed for determination of M. pneumoniae antibodies. This test allows the detection of antibodies in various immunoglobulin (Ig) classes similar to the previously described radioimmunoprecipitation test (RIP). SRIA has two advantages over RIP: first, it uses 100-fold less anti-Ig reagents than RIP; second, bound can be separated from unbound antigen more easily by the relatively heavy staphylococci. SRIA antibodies, belonging to the IgA class of Ig, could be detected in nasal secretions of volunteers infected intranasally with ts H43 of M. pneumoniae. In sera of patients with M. pneumoniae pneumonia antibodies to the IgG or the IgM class of Igs could be determined separately. This is especially important for an early diagnosis of M. pneumoniae disease.