[A method for the preparation of a Chlamydiae group-specific antigen on hela-229 cells infected with a strain of "Chlamydia trachomatis" for use in the complement fixation test (author's transl)].

A simple method for the preparation of a potent group-specific antigen on HeLa-229 cells infected with MRC-1 (LB) (TRIC/GB/MRC-1 Gf) strain of Chlamydia trachomatis is outlined. HeLa-229 cells are infected (MRC-1 strain, 102 inclusion-forming units per cell) with centrifugation at 4,000 g for 1 h in flat-bottomed vials. The cells are removed by brief trypsinization with 0.25% trypsin and put into 75 cm2 culture flasks (12 x 106 cells by flask) in BHK-21 medium supplemented with foetal bovine serum. The flasks are incubated for 5 days at 37 degrees C. The destroyed cell monolayer and the supernatant are centrifuged at 100,000 g for 1 h. The pellet is collected and resuspended in PBS and subjected to ultrasonic vibration for 30 min. This antigen may be used for detection of complement-fixing antibodies in lymphogranuloma venereum and ornithosis.