Serum specific IgA antibody to Chlamydia trachomatis in patients with chlamydial infections detected by ELISA and an immunofluorescence test

Sera obtained from 34 men with Chlamydia trachomatis positive non-gonococcal urethritis, 34 men with C trachomatis negative non-gonococcal urethritis, 42 women with acute salpingitis, 38 healthy women, and 34 healthy men were studied for the presence of specific serum C trachomatis IgA and IgG antibodies. Serological results were correlated with C trachomatis isolation in cell culture. An enzyme linked immunosorbent assay (ELISA) for C trachomatis specific serum IgA was employed using highly purified elementary bodies of C trachomatis serotype L2 grown in LLC-MK2 cells. Results obtained for C trachomatis IgA antibody by the ELISA test were compared with results obtained for the same sera by a single antigen immunofluorescence technique. A good correlation (r = 0.91) was found between two methods. Serum IgG antibody was also determined in the same sera by the immunofluorescence technique. Patients with C trachomatis positive non-gonococcal urethritis had a significantly (p less than 0.0005) higher prevalence (94.1%) of serum IgA antibody by ELISA compared with patients with C trachomatis negative non-gonococcal urethritis (20.5%) or healthy men (5.9%). Similarly, women with acute salpingitis had a significantly (p less than 0.005) higher prevalence of serum IgA antibody (45.2%) compared with healthy controls (5.2%). Comparable results were obtained for C trachomatis serum IgA antibody using the immunofluorescence technique. The prevalence of C trachomatis IgG antibody was significantly higher in patients with C trachomatis positive non-gonococcal urethritis (97.0%) compared with those with C trachomatis negative non-gonococcal urethritis (33.3%) and healthy controls (23.5%). The importance of using specific C trachomatis serum IgA in the identification of chlamydial infection is discussed.

An immunoperoxidase assay for the detection of specific IgA antibody in Epstein-Barr virus infections

A technique using indirect immunoperoxidase antibody was developed for the detection of specific serum IgA antibody to Epstein-Barr virus capsid antigen and early antigen. The IgA technique was compared with an immunofluorescence antibody method. Epstein-Barr virus IgA antibody against viral capsid antigen was detected in all nine patients with Epstein-Barr virus associated undifferentiated nasopharyngeal carcinoma, in 13 (72.2%) of 18 patients with infectious mononucleosis, in 21 (28.3%) of 74 patients with acute lymphoblastic leukaemia, and in six (20%) of 30 patients who had recently had kidney transplants. Epstein-Barr virus IgA antibody against viral capsid antigen was also detected in four (10%) of 40 healthy subjects, but it was not found in any of 20 cord blood samples. Epstein-Barr virus IgA antibody to early antigen was detected in six (66.6%) patients with nasopharyngeal carcinoma and in two (2.7%) patients with acute lymphoblastic leukaemia. The immunoperoxidase assay for Epstein-Barr virus specific IgA was simple, reliable, and rapid and correlated well (r = 0.94) with the immunofluorescence antibody technique.

A combined treatment in prevention of postgonococcal urethritis

The authors report a study carried out on 82 patients affected with gonococcal urethritis, in order to investigate the activity of minocyclin in the prevention of postgonococcal urethritis.

A simple immunoperoxidase method for detecting enteric adenovirus and rotavirus in cell culture

A technique which includes the use of indirect immunoperoxidase antibody (IPA) has been developed for detecting enteric adenovirus and rotavirus antigens in cell cultures and has been compared with immunofluorescence antibody assay (IFA). The IPA technique was as sensitive as the IFA. The number of positive cells detected by both techniques in tissue cultures was the same; false positive results were not observed. The applicability of IPA in clinical virology is discussed.

Rapid immunoperoxidase assay for detection of respiratory syncytial virus in nasopharyngeal secretions

Samples of nasopharyngeal secretions obtained from 70 infants and young children with acute respiratory disease were examined for the presence of respiratory syncytial virus by immunoperoxidase assay (IPA). The IPA was compared with the immunofluorescence assay and with cell culture isolation. Respiratory syncytial virus antigen-positive cells were detected by both IPA and immunofluorescence assay in 28 specimens; 25 samples were positive in cell culture. The agreement between virus isolation and IPA and IFA was 89%. The applicability of IPA to rapid viral diagnosis of respiratory syncytial virus infection is discussed.

Evaluation of a new latex agglutination test for detecting human rotavirus in faeces

Four methods for detecting rotaviruses (latex agglutination, electron microscopy, immunofluorescence and ELISA) have been compared on 57 faecal samples from children with acute diarrhoea. Complete agreement among the four techniques was found in 38 samples. One sample was positive by ELISA and latex agglutination but negative by the other two. For all the other samples there was agreement among three of the techniques only. In a blocking ELISA test, samples positive by ELISA only, turned out to be falsely positive. Assuming true positive or negative for those samples for which at least three techniques were in agreement, electron microscopy, ELISA and latex agglutination were more sensitive (96 per cent) than immunofluorescence (84 per cent). Electron microscopy was the most specific (96.4 per cent), followed by immunofluorescence (92.9 per cent), ELISA (89.4 per cent) and latex agglutination (85.9 per cent).

Virological course of herpes zoster in otherwise normal hosts

The virological course of herpes zoster infection in 42 otherwise normal hosts was studied by virus isolation and antibody titration. Varicella-zoster virus (VZV) was isolated from vesicle fluid from all three patients examined on the first day of the vesicular eruption and from five out of six examined on the second day. The isolation rate fell to one out of six patients on the seventh day of illness and VZV was not isolated from patients at a later stage of the illness. IgG antibodies were detected by IFAMA and ELISA, in sera from all the patients by the end of the first week of illness; IgG antibody titres were highest during the second and the third weeks. IgM antibodies to VZV were detected in sera from six of the 42 patients with herpes zoster after fractionation by ion-exchange chromatography.

A rapid immunoperoxidase assay for the detection of specific IgG antibodies to Chlamydia trachomatis

A technique, using indirect immunoperoxidase antibody (IPA), was developed for the detection of IgG antibody to Chlamydia trachomatis. The IPA technique employs glass slides with air-dried and acetone-fixed C trachomatis infected cells, which can be stored at -70 degrees C and used for several months. Antibody titres detected by IPA were comparable to those detected by the indirect fluorescent antibody technique.

Serum antibody profile against herpesviruses in renal transplant recipients

Forty-eight renal allograft recipients who had received a kidney graft 2 months to 8 years previously, were followed for the presence of serum antibody against Cytomegalovirus (CMV), Epstein-Barr virus (EBV), Herpes simplex virus (HSV), and Varicella-Zoster virus (VZV). These investigations were performed over a 6 months period and in at least two serum samples from each patient, obtained at intervals of 2-3 months. The presence of serological signs of recent or active infection were observed in 31 patients for CMV, in 22 patients for EBV (18 patients were positive both for CMV and EBV) and only in 3 patients for HSV, while no patients showed serological signs of recent or active infection by VZV.

Cytological and histopathological abnormalities of the cervix in genital Chlamydia trachomatis infections

Since genital infection with Chlamydia trachomatis may be associated with cervical abnormalities 160 patients with grandular ectopia attending a gynaecological outpatient clinic were examined for antibodies against C trachomatis, the presence of C trachomatis infection, and cytological and histopathological abnormalities of the cervix.A significantly higher incidence of histological dysplasia was found in women with glandular ectopia who had antichlamydial antibodies than in those without.

[Ultrastructural analysis of the effect of antimicrobial drugs on the development of Chlamydia trachomatis in cells cultured in vitro]

The Authors report the results of an ultrastructural study of the developmental cycle of Chlamydia trachomatis in cell cultures in vitro in the presence of inhibitors of te synthesis of DNA (mitomycin-C), RNA (actinomycin-D and rifampin) and proteins (oxytetracycline and chloramphenicol). The chlamidiae were grown to IUDR-pre-treated McCoy cell cultures and the drugs were added to the medium either immediately after the infection (in the presence of "elementary bodies" only) or after the appearance of the first "initial bodies" (14 hours after infection). The appearance of "initial bodies" or their multiplication was completely prevented in the infected cell cultures in the presence of mitomycin-C, actinomycin-D, rifampin and oxytetracycline added immediately after the infection or 14 hours after the infection, respectively. In the presence of chloramphenicol the appearance of "initial bodies" or their multiplication was possible, but their differentiation into "elementary bodies" was completely inhibited.

[The replication cycle of Chlamydia trachomatis and Chlamydia psittaci: ultrastructural analysis]

An ultrastructural comparative analysis is reported on the replication cycle of six strains of Chlamydia trachomatis, recently isolated, and Chlamydia psittaci strain 6BC, grown in cell cultures. Important morphological distinctions of the bacterial walls are documented. In Chlamydia trachomatis the cell wall seems more rigid. This causes, during the morphogenesis of the elementary body, its separation from the cell membrane with formation of an electron transparent space, which is not demonstrable in Chlamydia psittaci. As a result of this process, the appearance of "ghosts" and "mini reticular bodies" is documented. Budding and multiple fission are suggested as possible mechanisms of replication of Chlamydia trachomatis, in coexistence or/as alternative to binary fission.

[Antibodies against Chlamydia trachomatis in patients with non-gonococcal urethritis and in the healthy Italian population]

The Authors report the results of a study on the prevalence of serum antibodies against Chlamydia trachomatis among patients with non-gonococcal urethritis caused by Chlamydia trachomatis and diagnosed on the basis of the isolation of the microorganism in cell cultures, among patients with non-gonococcal urethritis of unknown etiology and in groups of healthy population, in Italy. The search for antibodies was performed both with complement-fixation tests in micro-titer system, using an antigen prepared from chicken embryo yolk sacs infected with the 6BC strain of Chlamydia psittaci, and with indirect immunofluorescence tests. The indirect immunofluorescence tests were carried out using as antigen the whole chlamydial inclusion developed in IUDR pre-treated McCoy cell cultures, grown on coverslips, and infected with the BU/434 strain of the LGV2 immunotype of Chlamydia trachomatis. The immunofluorescence tests proved to be much more sensitive than the complement fixation tests in detecting the presence of anti-chlamydial antibody both in patients with non-gonococcal urethritis and in the healthy population groups. The percentage of subjects possessing anti-chlamydial antibodies among the healthy population suggests a diffuse circulation of Chlamydia trachomatis infection. The possibility of employing the serological data in the diagnosis of the etiology of non-gonococcal urethritis is briefly discussed.

[Epidemiological aspects of salmonelloses in Turin. II: The presence of Salmonella in surface waters and sewerage waters of Turin]

The Authors have examined several sets of superficial water and of sewerage waters (respectively 44 and 27) in the metropolitan area of Turin in search of Salmonella bacteria.