A T-helper cell epitope overlaps a major B-cell epitope in human papillomavirus type 18 E2 protein.

Cultivated CD4+ T-helper cells from two patients with cervical adenocarcinoma showed responses to a peptide EKTGILTVTYHSETQRTK derived from an E2 protein of human papillomavirus type 18 (HPV 18), but not to a corresponding HPV 16 peptide (HKSAIVTLTYDSEWQRDQ). Serum antibodies in the HPV 18 peptide were also demonstrated in these patients. The GILT motif resembles a common pattern present in many T-cell epitopes, and is located at the beginning of an 11-amino acid-long A-helix structure close to the carboxyterminal end of HPV 18 E2. We conclude that two epitopes (a T-helper cell epitope and a B-cell epitope) overlap in the HPV 18 E2.     

Heat shock preconditioning modulates proliferation and apoptosis after superficial injury in isolated guinea pig gastric mucosa via an eicosanoid and protein synthesis-dependent mechanism

AIM: In restitution after superficial injury of the gastric mucosa, the epithelial continuity is restored by cellular migration. We have shown that heat shock preconditioning inhibits restitution after superficial injury. This study investigates the effect of heat shock preconditioning on tissue proliferation and apoptosis. EXPERIMENTAL DESIGN: Paired guinea pig gastric mucosae were mounted and perfused in Ussing chambers (37 degrees C). After heat shock preconditioning (42 degrees C) (30 min) and normothermic recovery (37 degrees C) (150 min) or normothermic perfusion, a superficial injury was induced by luminal exposure to 1.25 mol/L NaCl (5 min) followed by a 3 h restitution. During perfusion, the mucosa was exposed to 30 micromol/L arachidonic acid (AA) to enhance heat shock response, to 50 micromol/L quercetin (Q) to inhibit the metabolism of arachidonic acid via lipoxygenases, to 50 micromol/L indomethacin (In) to inhibit the metabolism of arachidonic acid via cyclo-oxygenases, or to 150 micromol/L cycloheximide (CHX) to inhibit de novo protein synthesis. After the experiment the mucosa was prepared for immunohistochemical analysis of the expression of Mib-1 proliferation antigen and pro-apoptotic protein Bax. RESULTS: Heat shock decreased Mib-1/Bax ratio and this effect was maintained after superficial injury and exposure to Q, to AA+CHX or to In+CHX. Exposure to CHX, to AA, to In+Q, to In+AA, In+AA+Q or to In+AA+CHX, however, blocked the effect of heat shock preconditioning. The decreasing effect of heat shock preconditioning on Mib-1/Bax ratio could be reversed by exposure to AA+Q or to In. CONCLUSION: The heat-preconditioning-induced effects on the mucosa are reversible and sensitive to exogenous pharmacological modulation. Heat shock preconditioning inhibits proliferation of superficially injured isolated gastric mucosa by a mechanism involving eicosanoid pathways and de novo protein synthesis.     

Antigen specific serum antibody response to Chlamydia trachomatis in patients with acute pelvic inflammatory disease.

Sera from 35 patients with acute pelvic inflammatory disease (PID) with and without Chlamydia trachomatis confirmed by culture and sera from 19 control patients with neither evidence of pelvic infection nor C trachomatis infection were studied for the presence of serum IgG, IgA, and IgM antibodies to C trachomatis using enzyme immunoassay (EIA) and immunoblotting techniques. There was no correlation between the antibody concentrations in the EIA and the spread of chlamydial infection, as determined by cervical, endometrial, and laparoscopic sampling for chlamydia. The immunoblot analysis showed antibodies to the major outer membrane protein (MOMP) of C trachomatis elementary bodies in all patients who had had C trachomatis isolated. Reactivity was also frequently observed against the 68, 62, 60, 45, and 31 kilodalton antigens. About 20 antigenic polypeptides were identified. Differences in antibody prevalence to specific chlamydial antigens, however, were not related to the site of chlamydial isolation or serum antibody concentrations observed with the EIA. The results indicate that patients with PID with and without upper genital tract infection with C trachomatis cannot be differentiated by reactivity of sera to specific chlamydial polypeptide antigens. The determination of a specific serum IgA antibody response by EIA was the most effective single test to discriminate between patients with and without acute chlamydial infection.     

Chlamydia pneumoniae infection in human monocytes

Chlamydia pneumoniae infection has been associated with cardiovascular diseases in seroepidemiological studies and by demonstration of the pathogen in atherosclerotic lesions. It has the capacity to infect several cell types, including monocyte-derived macrophages, which play an essential role in the development of atherosclerosis. However, the persistence of C. pneumoniae in mononuclear cells is poorly understood. To study the morphology and biological characteristics of the infection, human peripheral blood monocytes were infected with C. pneumoniae. Freshly isolated monocytes resisted the development of infectious progeny, and confocal and transmission electron microscopy showed that the morphology of the inclusions and chlamydial particles was abnormal. Addition of tryptophan or antibodies against gamma interferon did not diminish the inhibition of C. pneumoniae, suggesting that other factors are involved in the chlamydiostatic activity of the monocytes. Chlamydial mRNA was expressed at least 3 days after infection, however, and a capability for infected monocytes to induce a positive lymphocyte proliferative response was detected for up to 7 days, indicating that C. pneumoniae remains metabolically active in the monocytes in vitro. These results are in accordance with the hypothesis that C. pneumoniae may participate in the maintenance of local immunological response and inflammation via infected monocytes and thus enhance atherosclerosis.     

Detection of Mycoplasma hominis antigen in clinical specimens by using a four-layer modification of enzyme immunoassay (EIA)

A 4-layer modification of enzyme immunoassay (EIA) was developed for the detection of Mycoplasma hominis antigen in clinical specimens. Microtiter plates were sensitized with rabbit anti-mycoplasma immunoglobulin, guinea pig anti-mycoplasma immunoglobulin was used as the secondary antibody, and horseradish peroxidase-conjugated anti-guinea pig immunoglobulin was used as the indicator antibody. The specificity of the assay was confirmed by using guinea pig immunoglobulins from preimmunization sera. The sensitivity of the assay is down to 10 ng/ml of antigen protein. Marked cross-reactivity was demonstrated for different strains within the species M. hominis, whereas the other genital mycoplasma species tested showed no reactivity in the assay. A comparison was made of EIA and conventional culture of vaginal specimens from 24 women. All 6 specimens positive by culture were also positive for M. hominis antigen by EIA. Antigen detection by EIA is a sensitive, rapid and simple method for the detection of M. hominis in clinical specimens.     

Use of AffiProbe HPV test kit for detection of human papillomavirus DNA in genital scrapes.

The presence of human papillomavirus (HPV) DNA in cervical and vaginal scrapes was analyzed by the AffiProbe HPV test kit (Orion Corp., Orion Pharmaceutica, Helsinki, Finland), which is a 1-day solution hybridization test for HPV type 6/11, 16, or 18. The AffiProbe test was compared with a commercially available dot blot test (ViraPap and ViraType tests; Life Technologies Inc., Gaithersburg, Md.). The study group consisted of 178 patients seen in a gynecological outpatient clinic. Altogether, 64 specimens (36 cervical and 28 vaginal scrapes) from 49 patients were positive by the AffiProbe test. Concurrently collected cervical scrapes from 174 patients were available for the reference test, which yielded 27 positive results for HPV type 6/11 or 16/18 and 25 positive results for HPV type 31/33/35. Agreement as to the presence of HPV type 6/11, 16, or 18 by the two tests was reached in 85% of the specimens. Eleven cervical specimens were positive by the AffiProbe test only, and nine cervical specimens were positive by the ViraType test only. Independent evidence obtained by the polymerase chain reaction, repeat examination, or the concurrent presence of HPV DNA in vaginal or vulval epithelium supported the AffiProbe and the ViraType test results for 6 of the 11 and 6 of the 9 specimens with discrepant results, respectively. Thus, the DNA tests had similar sensitivities for HPV type 6/11, 16, and 18 DNAs, but the results were obtained within 1 day by the AffiProbe test, whereas results for the ViraPap and ViraType analyses required from 4 days to 2 weeks.     

Solid-phase enzyme immunoassay for Chlamydial antibodies.

An enzyme immunoassay (EIA) for chlamydial immunoglobulin G antibodies was developed by using microtiter wells coated with partially purified reticulate bodies of Chlamydia trachomatis serotype L2, grown in McCoy cells, and uninfected McCoy cells as a control. Duplicate testing of a single serum dilution, 1:500, was found to be sufficient. A good correlation between positive reactions was observed in a comparative study of 421 patient sera with the EIA and an inclusion immunofluorescence test. A good correlation between positive reactions was also observed in a comparative study of 140 patient sera with EIA and microimmunofluorescence tests in which chlamydial elementary or reticulate bodies were used as antigens. Sera of 77 healthy control individuals with low titers in inclusion immunofluorescence or complement fixation tests gave negative results in the EIA. Immunoblotting experiments showed that the major antigenic component in the EIA antigen was a protein with an Mr of 39,000.