Comparison of iodine- and fluorescein-labeled monoclonal antibodies for detection of Chlamydia trachomatis inclusions in cells grown in glass vials.

A fluorescein-labeled monoclonal antibody was compared with the iodine stain for the detection of chlamydial inclusions in McCoy cells grown on cover slips in glass vials. The remainder of the original specimen extracts in 2-sucrose phosphate transport medium from 100 specimens (50 male, urethra; 50 female, cervix), stored at -70 degrees C and previously determined to be culture positive for Chlamydia trachomatis by the iodine stain, were inoculated into vials containing monolayers of McCoy cells. Cover slips were coded and examined microscopically after 40 hr at 35 degrees C. The mean numbers of inclusions detected by iodine and by immunofluorescence were the same. One-half of the specimens had eight or fewer inclusions present. There was a trend indicating that less time was required for microscopic examination of cover slips for chlamydial inclusions with immunofluorescence than with the iodine-staining method. The tagged monoclonal antibody is a high-quality immunodiagnostic reagent for use in the immunofluorescence test; however, our data derived from stored specimen extracts indicate equivalence of detection of inclusions in the glass vial system compared to iodine.