Immunocytochemical demonstration of Chlamydia infection in the urogenital tracts

Processing of cytological specimens

Individual cells often need to be examined with antibodies apart from the surrounding tissue. They may be cells in fluid, cells encased in mucus from a swab, or cells directly extracted from a piece of tissue. Cells can be viewed on a glass slide as cell smears produced from a cell enriched source, introduced as a touch preparation from a piece of wet tissue, concentrated on a slide by the use of a cytocentrifuge, or applied directly to a slide from a solid medium such as a cotton swab. These cell preparations can then be optimally fixed in weakly or nondenaturing solutions such as acetone or those that are alcohol based. They can also be postfixed in formalin if desired. Incubation in buffers containing 0.25% Triton X-100 and 5% dimethylsulfoxide (DMSO) allow for easier antibody penetration. The endogenous peroxidase enzyme or oxidative compounds can be quenched in a mild hydrogen peroxide solution. The sections are then ready to test with antibody after an incubation in a normal serum solution blocks any available charged sites.

Intracytoplasmic vacuoles in cervical smears: relationship to chlamydial inclusions--morphology, mucin histochemistry, and immunocytochemistry

Cytomorphology, mucin stains, and immunocytochemistry were used to determine the characteristics of intracytoplasmic vacuoles in cervical smears and their relationship to chlamydial infections. Three study groups were examined: A) cervical smears containing intracytoplasmic vacuoles suggesting chlamydial infection: B) cervical smears from patients known to be either culture positive or culture negative for chlamydia; and C) control smears of chlamydia-infected McCoy cell cultures. Forty-nine smears containing vacuoles suspected of being chlamydial inclusions were studied. In 21 of 31 smears the vacuoles were shown by histochemistry to contain mucin. Immunoperoxidase staining performed on the remaining 18 smears revealed only two vacuoles to be chlamydial inclusions. Of 38 smears from chlamydia-culture-positive patients, only 4 showed chlamydial inclusions by immunoperoxidase methods. Of 30 smears from chlamydia-culture-negative patients, none were positive by immunoperoxidase staining. The "nebular body" of Shiina appears to be the most specific cytomorphologic evidence of chlamydial infection in cervical smears, but distinction from mucin vacuoles and other nonspecific vacuoles is difficult. The immunoperoxidase technique is unlikely to be useful in diagnosis in cervical smears unless samples are specifically obtained from the endocervical canal by endocervical brushing.

Use of the Cytobrush for concurrent endocervical cytology and chlamydia sampling

In 899 women attending a genitourinary medicine clinic Chlamydia trachomatis was tested for using both a Cytobrush and a conventional swab. In 425 cases, the Cytobrush was used for concurrent cytology and chlamydia sampling. Both methods were equally effective in the detection of chlamydia, and, in addition, the Cytobrush gave a higher yield of inclusion bodies per sample. The use of the same instrument for both cytology and chlamydia screening may represent a saving in time and money.

Comparison of DNA probe, monoclonal antibody enzyme immunoassay, and cell culture for the detection of Chlamydia trachomatis

A total of 201 endocervical specimens were obtained from patients with a clinical or epidemiological history suggestive of chlamydial infection. These specimens were tested by DNA probe (Gen-Probe, San Diego, Calif.) and the IDEIA III (Boots-Celltech, Berkshire, United Kingdom) monoclonal antibody enzyme immunoassay and compared with cell culture for detection of Chlamydia trachomatis. Discrepancies between cell culture and antigen detection methods were resolved by direct fluorescent-antibody testing. In a population with a 17.4% prevalence, the sensitivities and specificities of these assays were 82.8 and 99.4%, respectively, for the DNA probe assay and 97.1 and 98.1%, respectively, for the IDEIA III.