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

Shift work influences the outcomes of Chlamydia infection and pathogenesis

Shift work, performed by approximately 21 million Americans, is irregular or unusual work schedule hours occurring after 6:00 pm. Shift work has been shown to disrupt circadian rhythms and is associated with several adverse health outcomes and chronic diseases such as cancer, gastrointestinal and psychiatric diseases and disorders. It is unclear if shift work influences the complications associated with certain infectious agents, such as pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility resulting from genital chlamydial infection. We used an Environmental circadian disruption (ECD) model mimicking circadian disruption occurring during shift work, where mice had a 6-h advance in the normal light/dark cycle (LD) every week for a month. Control group mice were housed under normal 12/12 LD cycle. Our hypothesis was that compared to controls, mice that had their circadian rhythms disrupted in this ECD model will have a higher Chlamydia load, more pathology and decreased fertility rate following Chlamydia infection. Results showed that, compared to controls, mice that had their circadian rhythms disrupted (ECD) had higher Chlamydia loads, more tissue alterations or lesions, and lower fertility rate associated with chlamydial infection. Also, infected ECD mice elicited higher proinflammatory cytokines compared to mice under normal 12/12 LD cycle. These results imply that there might be an association between shift work and the increased likelihood of developing more severe disease from Chlamydia infection.

The treatment and follow up of adult chlamydial ophthalmia

Sixty two patients diagnosed as having adult chlamydial ophthalmia were treated with oral doxycycline and roxithromycin in association and tetracycline eye wash for 2 weeks. Chlamydial ophthalmia was diagnosed by laboratory detection of the micro-organism in ocular specimens using direct immunofluorescent monoclonal antibody staining for Chlamydia trachomatis, chlamydial culture in cycloheximide treated McCoy cells, and Giemsa staining. An immunoenzymatic method for detection of specific IgG and IgA in patients' serum was used as an additional test to confirm the diagnosis. All patients were reexamined 3 weeks after completing their course of antibiotics and in the case of persistent infection a further course of treatment was given. With this treatment regimen 48 out of 62 patients (77.4%) were cured after three courses. Because of the risks of an inadequate response to therapy, we recommend a proper post-treatment follow up in all patients with chlamydial eye infections.

Occurrence of antibodies against chlamydial lipopolysaccharide in human sera as measured by ELISA using an artificial glycoconjugate antigen

An artificial glycoconjugate containing, as a ligand, the deacylated carbohydrate backbone of a recombinant Chlamydia-specific lipopolysaccharide was used as a solid-phase antigen in ELISA to measure antibodies against chlamydial LPS. The specificity and reproducibility of the assay was shown by using a panel of prototype monoclonal antibodies representing the spectrum of antibodies also occurring in patient sera. These mAbs recognized Chlamydia-specific epitopes [alpha 2-->8-linked disaccharide of 3-deoxy-D-manno-octulosonic acid (Kdo) or the trisaccharide alpha Kdo-(2-->8)-alpha Kdo-(2-->4)-alpha Kdo] or those shared between chlamydial and Re-type LPS (alpha Kdo, alpha 2-->4-linked Kdo disaccharide). The assay was used to measure IgG, IgA and IgM antibodies against chlamydial LPS in patients with genital or respiratory tract infections. In comparison to the results obtained with sera from blood donors, it became evident that both types of infection result in significant changes in the profile of LPS antibodies.

Chlamydial IgG and IgA in serum and follicular fluid among patients undergoing in vitro fertilisation

The point prevalence of IgG and IgA antibodies to Chlamydia was analyzed in serum and follicular fluid in 63 patients undergoing in vitro fertilisation (IVF) in comparison to sera of 298 healthy women by the single serovar (L2) inclusion immunoperoxidase assay (IPA). The presence of specific IgG and IgA to Chlamydia in follicular fluid was demonstrated. No statistical association was found between the presence of specific Chlamydia IgG and IgA in serum and follicular fluid to oocyte fertilization. The positive predictive value for mechanical infertility of Chlamydia IgG at titers of greater than or equal to 128 and IgA titers at greater than or equal to 16 was 91 and 92%, respectively, in this high-risk group for mechanical infertility. Multiple regression analysis singled out Chlamydia IgG levels as a major contributor to the variance between the groups of infertile patients.

Laboratory survey of Chlamydia trachomatis ocular infections

The authors used immunofluorescence and immunoperoxidase tests to study a group of 101 patients with acute or chronic conjunctivitis, etiologically unrelated to conventional bacterial pathogens, and a control group of 30 healthy adults. Positive titers of IgG in serum and of IgA in lacrimal secretions against Chlamydia, detected by IPA, correlated with the identification of microorganisms by direct immunofluorescence. The use of both tests allows a precise evaluation of the stage of the infection and of its evolutive pattern.

The association between chlamydial-specific IgG and IgA antibodies and pregnancy outcome in an in vitro fertilization program

Chlamydial-specific IgG and IgA antibodies were determined by a single serovar (L2) immunoperoxidase assay (IPA) in the serum of all patients that have conceived in an in vitro fertilization and embryo transfer (IVF & ET) program (n = 106) and in a group of patients that went through the program at the same period of time and did not conceive (n = 94). The prevalence rate of elevated IPA IgG (titers greater than or equal to 1:128) and IPA IgA (titers greater than or equal to 1:16) specific to chlamydiae was significantly higher (P less than 0.001) in the IVF & ET pregnancy loss and nonconception groups ("failures") versus the IVF & ET term pregnancy group ("successes") (74 vs 47%, odds ratio = 4.1, and 34 vs 14%, odds ratio = 4.3, respectively). Stepwise discriminant analysis revealed that elevated specific chlamydial IgG had the greatest effect on the variance between successes and failures in this study group. Our study indicates the possible role of past or chronic active chlamydiae infection on the "take-home baby rate" in an IVF & ET program.

Significance of immunoglobulin A titres in the diagnosis of urogenital chlamydial infections

The significance of chlamydial serum IgA compared with IgM and IgG in the diagnosis of urogenital chlamydial infection was evaluated using 120 sera from different categories of patients. In urethritis patients both IgM and IgA antibodies were not found to be present consistently, whereas in patients with deep-seated chlamydial infection, IgA was more often present. Although of limited value in superficial infections, demonstration of IgA antibodies may be of value in the diagnosis of deep-seated chlamydial infections.

Detection of specific IgG and IgA antibodies to Chlamydia trachomatis in women with salpingitis confirmed by laparoscopy

The sera from 12 consecutive symptomatic women with laparoscopy-confirmed salpingitis were screened for the presence of specific IgG and IgA antibodies to Chlamydia trachomatis by a single antigen (L-2) immunoperoxidase assay. All women were found to have IgG and IgA antibodies to C trachomatis. Six women had positive endocervical cultures for C trachomatis, and one of these had positive cultures from the conjunctiva and fallopian tubes. Serum chlamydial IgA antibodies may serve as markers for active infection with C trachomatis regardless of whether organisms can be identified by culture or direct fluorescent antibody techniques from endocervical or fallopian tube samples.

The significance of the ipazyme IgA and IgG antibody test in the diagnosis of urogenital chlamydial infections

Urogenital specimens from 200 male and female patients were cultivated for the detection of C. trachomatis. For comparison, serum of the same patients was investigated with the Ipazyme IgA and IgG test. This comparison of culture and serological tests revealed a sensitivity of the IgA Ipazyme test of 56% and a specificity of 81%. For the IgG Ipazyme test, the corresponding values were 77% and 39%. The sensitivity of the conventional immunofluorescence test reached 46% and its specificity was 50% for the same group of patients. Antibiotic treatment of 13 IgA-positive patients resulted in a significant decrease of the titre in only one case. The introduction of the Ipazyme test does not open a new aspect in chlamydial serology, i.e. the diagnostic value of serology for the detection of a current chlamydial infection remains low.

Prevalence of IgA and IgG antichlamydial antibodies in women in the third trimester of pregnancy

The prevalence of serum antichlamydial IgA and IgG antibodies was investigated by screening 77 randomly selected patients who were in the third trimester of pregnancy. An indirect immunoperoxidase assay that quantitates IgA and IgG was used for screening. Twenty-five women had both IgA and IgG antibodies; an additional ten women had only IgG antibodies. These findings suggest that greater than 45 percent of pregnant women tested had been exposed to Chlamydia trachomatis, and more than 32 percent had evidence of active infection.

Chlamydial antibodies in farmers in north-west England

Because of recent reports of abortion in farmers' wives following infection with ovine strains of Chlamydia psittaci during pregnancy, the distribution of chlamydial antibodies was studied in rural populations in north-west England, where endemic chlamydial infection with abortion is common in sheep. Immunoperoxidase assays with C. trachomatis and ovine C. psittaci showed no significant differences in either the frequency or titres of antibodies between sheep farmers and other types of farmer or non-farming adults living in the same areas. The frequency and titres of antibodies in farmers' wives were no greater than in farmers, and were unrelated to their previous obstetric history or type of farming. Overall, 62/255 (24%) of this rural population had antibody detected by C. trachomatis antigen and only 30/255 (13%) detected by C. psittaci antigen. The possible significance of these findings is discussed. This survey does not suggest that the risk of infection with C. psittaci is especially high in people working with sheep, but the complications following infection during pregnancy deserve the specific instructions that have been given to pregnant women to avoid exposure, especially during lambing, in farming and veterinary work.

Diagnosis of Chlamydia trachomatis infection--culture versus serology

The diagnostic value of different laboratory methods in detecting Chlamydia trachomatis infections in high risk groups was analysed. The efficiency of a direct specimen test was compared with serology (IgG and IgM ELISA) and culture in L929 cells, stained either with fluorescein conjugated monoclonal antibodies or with iodine. Patients (no. = 1041) with localized genital infections attending a STD clinic, sexual contacts and patients with ascending infections from urological and gynecological clinics were examined. Chlamydia trachomatis was detected in 225 patients: 210 (93.3%) were reactive in the direct test (smears stained with monoclonal antibodies), whereas culture missed only 5 (sensitivity 97.8%) when stained by the same method. Cultures stained with iodine produced the lowest recovery rate (73.8%), but this rate increased to 80.9% when a second passage was performed. In addition the prevalence of Neisseria gonorrhoeae, Mycoplasma hominis, Ureaplasma urealyticum, Candida albicans and Trichomonas vaginalis was investigated. In patients with non-gonococcal urethritis (no. = 331) and cervicitis (no. = 353), Chlamydia trachomatis was isolated in 32.3% and 12.8% respectively. However, this pathogen could be isolated in only 3 (15.8%) out of 19 patients with epididymitis and 15 (14%) out of 107 patients with adnexitis, although 66.7% and 93.3% respectively had specific IgG antibodies. Specific IgM could by detected with a sandwich ELISA in patients with adnexitis (46.7%), epididymitis (33.3%), cervicitis (22.2%), non-gonococcal urethritis (14%) and in the sexual partners of patients with genital infections (35.7%). The direct specimen test with monoclonal antibodies is the method of choice for the diagnosis of a C. trachomatis infection in patients with urethritis and cervicitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of diagnostic tools for adult chlamydial keratoconjunctivitis

Conjunctival smears and serum specimens of 150 patients with presumed chlamydial keratoconjunctivitis were evaluated over a period of 16 months and compared to age- and sex-matched healthy controls. Sensitivity, specificity, and predictive values of fluorescent monoclonal antibody (FMAb) direct tests, IgG single antigen tests for the detection of serum antibody (IgG-IFT), and IgA and IgG immunoperoxidase tests (IgA-IPAs and IgG-IPAs) for serum antibody were compared to McCoy cell culture techniques in a nonoptimized clinical setting. Thus, FMAb sensitivity was 100%, specificity was 52%, and predictive value was 30%. IgG-IFT sensitivity was 94%, specificity was 67%, and predictive value was 37%. IgA-IPA sensitivity was 100%, specificity was 70%, and predictive value was 40%. The IgG-IPA was sensitive but nonspecific. With respect to the current epidemiologic situation in our area, FMAb and IgA-IPA in addition to McCoy cell culture techniques may represent valuable diagnostic tools for the detection of chlamydial disease.

Fate of Chlamydia trachomatis in human monocytes and monocyte-derived macrophages

The fate of Chlamydia trachomatis (L2/434/Bu) in human peripheral blood monocytes and human monocyte-derived macrophages was studied by transmission electron microscopy (TEM) and by measuring the yield of infectious C. trachomatis in one-step growth experiments. Two main types of phagosome were seen by TEM in the cytoplasm of C. trachomatis-infected human monocytes (1 h postinfection [p.i.]): one in which the elementary body (EB) was tightly surrounded by the membrane of the phagosome and another in which the EB appeared in an enlarged phagosome. Later, 24 to 48 h p.i., each phagosome contained a single EB-like particle, an atypical reticulate body, or a damaged particle. One-step growth experiments showed that infection of human monocytes with C. trachomatis results in a decrease of infectious particles between 24 and 96 h p.i., whereas infection of the monocytes by C. psittaci (6BC strain) results in productive infection with, however, a 3.5-log lower yield than in control MA-104 cells. In contrast to the abortive replication of C. trachomatis in monocytes, monocyte-derived macrophages permitted replication as indicated by one-step growth experiments and TEM. in C. trachomatis-infected, monocyte-derived macrophages 72 h p.i., inclusions of two kinds were observed by TEM. One was very similar to the typical inclusions appearing in infected MA-104 (control) cells; the other was atypical, pleomorphic, often contained "channels," and held relatively few EB and reticulate bodies, some of which appeared damaged or abnormal. The significance of the responses to infection with C. trachomatis in monocytes compared with monocyte-derived macrophages and the role of these cells in sustaining chronic or latent infection and in dissemination of the infection to various parts of the body is discussed.

Recent advances in Chlamydia trachomatis

Chlamydia trachomatis is an obligate intracellular energy parasitic bacterium with a genome of 660 X 10(6) daltons, possessing a plasmid and unique life cycle which includes the differentiation of the infective elementary body to a replicative reticulate body. C. trachomatis is the etiological agent of trachoma, which affects approximately 500 million people in developing countries. Recently it became evident that in industrialised Western nations certain strains of C. trachomatis are the most common cause of sexually transmitted infections such as non-gonococcal urethritis, cervicitis, endometritis, salpingitis and subsequent ectopic pregnancies or infertility, perihepatitis, neonatal conjunctivitis and pneumonia, adult conjunctivitis and epididymitis. Since C. trachomatis infections are often asymptomatic, widespread screening of sexually active young people is needed in order to initiate early antibiotic treatment which may prevent serious complications such as ectopic pregnancies and infertility. Development of sensitive and simple techniques for mass screening for detection of Chlamydia in excretions as well as techniques for detection of specific markers of chronic internal infections (such as Chlamydia specific IgA antibodies) is of great importance.

Serum IgG and IgA antibodies specific for Chlamydia trachomatis in salpingitis patients as determined by the immunoperoxidase assay

The feasibility of applying elevated Chlamydia trachomatis specific IgG antibody and serum IgA antibodies as a non-invasive screening test for C. trachomatis associated salpingitis was analysed in 54 salpingitis patients and 294 apparently healthy women by the single antigen (L2) immunoperoxidase assay (IPA). The prevalence rate of C. trachomatis IgG antibody (titre greater than or equal to 64) was significantly higher in the salpingitis patients in comparison to control (67% versus 23%). The prevalence rate of elevated C. trachomatis IgG titres (greater than or equal to 128, greater than or equal to 256 and greater than or equal to 512) was significantly higher in the salpingitis patients as compared to the controls. For example, at an IgG titre of greater than or equal to 128 the prevalence rate was 57% in the salpingitis patients and 8% in the healthy controls (p less than 0.0001). The prevalence of C. trachomatis IgA antibodies (titre greater than or equal to 16) was significantly higher in salpingitis patients in comparison to controls (37% versus 4%). The prevalence of elevated IgA titres (greater than or equal to 32 and greater than or equal to 64) was found to be significantly higher in salpingitis patients as compared to controls. All the IgG seropositive salpingitis patients were also found to have C. trachomatis IgG antibodies. It appears that testing for IgG antibodies at a serum dilution of 1:128, and for IgA antibodies at a dilution of 1:16 by the IPA test comprises the best combination for the differentiation between the salpingitis patients and apparently healthy controls, and it is suggested that this be used as a marker of active C. trachomatis infection.

Determination of specific cytomegalovirus IgM antibodies using infected air dried cells and isolated nuclei by immunoperoxidase assay

A simple immunoperoxidase assay (IPA), adapted for detection of serum IgM antibodies to cytomegalovirus (CMV) is described. The antigen consisted of CMV infected human embryonic fibroblasts or isolated nuclei. The sera were absorbed with aggregated gamma-globulins prior to testing. Rabbit anti-human IgM peroxidase conjugate was used to detect IgM bound to viral antigen. In parallel the enzyme linked immunosorbent assay (ELISA) technique was used to determine IgG and IgM antibodies to CMV, respectively. All patients with acute CMV infections who were tested had CMV-specific IgM antibodies by IPA, both whole cell and nuclei antigen. The maximal IgM titers were higher by ELISA than by IPA but in 3 of the CMV patients IgM was detected earlier by IPA (with both types of antigens) than by ELISA. In 3 of 5 transplant patients with recurrent CMV infection IgM was demonstrated by immunoperoxidase techniques, while by ELISA IgM was demonstrated in only 2 of them. No cross reactivity with other herpes viruses was observed. The described IPA is simple, rapid and has the potential for widespread use in routine laboratories.

Immunoperoxidase assay for the detection of specific IgG antibodies to Hantaan virus

A technique, using indirect immunoperoxidase antibody (IPA), was developed for the detection of IgG antibody to Hantaan virus. The same protein A-peroxidase conjugate was used with mouse, rat and human sera. The IPA technique employs glass slides with air-dried gamma-ray-inactivated and acetone-fixed Hantaan-infected Vero-E6 cells. Antibody titers detected by IPA was comparable to those detected by the indirect fluorescent antibody technique.

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 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.