Immunoblot of EB probed with serum samples collected from male mice infected in the meatus urethra with C. trachomatis. Lane 1, molecular weight standards; lanes 2 to 8, serum samples collected at weeks 1 to 7 p.i.; lane 9, EB probed with monoclonal antibodies to the 150,000, 60,000 (crp), 40,000, and 28,000 MW proteins and to LPS.