Serologic diagnosis of Lymphogranuloma venereum by counterimmunoelectrophoresis with a Chlamydia trachomatis protein antigen.

Previously a protein antigen was identified which was common to members of the species Chlamydia trachomatis and to which antibody could be demonstrated in human sera by two-dimensional immunoelectrophoresis. The antigen has been purified by immunoadsorption chromatography, and an exploration undertaken to determine whether the detection of antibody to this antigen by counterimmunoelectrophoresis would be useful for the diagnosis of C. trachomatis infections. Antibody was found in 43 of 45 (96%) sera from patients with lymphogranuloma venerum proven by either isolation or other serologic methods. No positive reactions were observed in 50 patients with nongonococcal urethritis, 38 of whom had evidence of antibody as measured by microimmunofluorescence with whole organism antigen. Sera were also negative from 50 normal individuals, 10 persons with gonorrhea, and 2 patients with psittacosis. Counterimmunoelectrophoresis with purified C. trachomatis protein antigen appears to be a useful serologic test for diagnosis of lymphogranuloma venereum.