Immunoassay for detecting Chlamydia trachomatis major outer membrane protein.

The development of a solid-phase immunoassay for the detection of the 39,500-dalton major outer membrane protein of the Chlamydia trachomatis lymphogranuloma venereum serotype L2 is described. The test uses immunoadsorbent-purified rabbit anti-L2 major outer membrane protein immunoglobulin G (IgG) passively adsorbed to microtiter plates as a capture antibody. This same IgG antibody was either conjugated to horseradish peroxidase or radioiodinated with 125I and used as a probe to detect major outer membrane protein bound to immobilized IgG. At its greatest sensitivity, the test was capable of detecting 0.5 to 1 ng of purified major outer membrane protein, 5 X 10(3) elementary body inclusion-forming units, and approximately 100 C. trachomatis intracytoplasmic inclusions per assay.