Recent advances in Chlamydia trachomatis

Microbial infection, inflammation and epithelial ovarian cancer

Ovarian cancer is the most common, and life-threatening, type of female gynecological cancer. The etiology of ovarian cancer remains unclear, and there are currently no effective screening or treatment methods for the disease. Microbial infection serves a marked function in inducing carcinogenesis. A number of studies have identified pelvic inflammatory disease as a risk factor for epithelial ovarian cancer. Thus, it is hypothesized that microbial infection may contribute to ovarian cancer. In the present review, the microorganisms that have been identified to be associated with ovarian cancer and the underlying molecular mechanisms involved are discussed. Infection-induced chronic inflammation is considered an important process for carcinogenesis, cancer progression and metastasis. Therefore, the pathological process and associated inflammatory factors are reviewed in the present paper.

TNF and PGE(2) in human monocyte-derived macrophages infected with Chlamydia trachomatis

In this study levels of prostaglandin E₂ (PGE₂), tumour necrosis factor (TNF) and interleukin-1 (IL-1) alpha in medium from monocyte derived macrophages (MdM) infected with Chlamydia trachomatis (L₂/434/Bu or K biovars). TNF and PGE₂ were found in both cases while IL-1 alpha was not detected. Both TNF and PGE₂ levels were higher in the medium of the MdM infected with K biovars. TNF reached maximum levels 24 h postinfection, and then declined, while PGE₂ levels increased continuously during the infection time up to 96 h post-infection. Addition of dexamethasone inhibited production of TNF and PGE₂. Inhibition of PGE₂ production by indomethacin resulted in increased production of TNF, while addition of PGE₂ caused partial inhibition of TNF production from infected MdM.

Persistence of antichlamydial antibodies after treatment of acute salpingitis with doxycycline

The effect of treatment with doxycycline on serum IgG and IgA antichlamydial antibodies was evaluated in 33 women who had had acute salpingitis associated with high titers of serum IgG (> or = 1:128) and/or IgA (> or = 1:16) antichlamydial antibodies. Overall, 29 women (87.9%) remained with high titers of IgG and/or IgA antibodies. No change or insignificant change in IgG antibody titer was demonstrated in 21 women (63.6%) and in IgA antibody titer in 21 women (63.6%). Positive seroconversion or a significant increase (> or = 4-fold) in IgG antibody titer was demonstrated in eight women (24.2%) and in IgA antibody titer in six women (18.1%). Negative seroconversion or a significant decrease in IgG antibody titer was demonstrated in four women (12.1%) and in IgA antibody titer in six women (18.1%). It is concluded that in most patients who had acute salpingitis associated with pretreatment high titers of serum antichlamydial antibodies, posttreatment titers may remain high even if treatment with doxycycline results in complete resolution of clinical signs and symptoms of the disease.

Experimental epididymitis due to Chlamydia trachomatis in rats

A new animal model of epididymitis due to Chlamydia trachomatis was developed. Adult male Wistar rats were inoculated in the vas deferens with C. trachomatis biovar mouse pneumonitis. After infection, C. trachomatis was recovered from the epididymides for up to 90 days. At day 30, organisms were also reisolated from the testes. Clinical findings included enlargement of infected epididymides and concurrent atrophy of the ipsilateral testes. Histological lesions in the epididymides consisted of pyogranulomatous inflammation, abscesses, and spermatic granulomas. Infection of the testis by C. trachomatis was associated with pyogranulomatous changes. In addition, testicular degeneration, characterized by moderate to severe loss of the germinal epithelium, was noted. Chlamydial antigen was detected within epithelial cells, intratubular macrophages, and macrophages in the stroma of the epididymis by immunoperoxidase staining. This rat model of chlamydial epididymitis appears to clinically and histopathologically mimic the human disease. This model offers the opportunity for further studies on the pathogenesis and sequelae of chlamydial epididymitis.

Epidemiology and therapy of Chlamydia trachomatis genital infection in women

Out of 1172 females recruited in a screening program for genital infections, 144 (12.28%) were cervical and/or urethral positive for Chlamydia trachomatis (Ct) by enzyme immunoassay (EIA). Patients positive for Ct showed no significant differences in terms of demography, sexual practices and clinical evidence as compared to a control group formed by Ct-negative females randomly selected. Historical data showed a higher frequency of previous pelvic inflammatory disease (PID) in patients as compared to controls. 11 of the 94 patients' partners tested were sperm positive for Ct. Of the 63 patients for whom therapeutic data were available, 38 were treated with josamycin, 16 with tetracycline and the others with different drugs. After treatment, EIA for Ct was negative for 92.1% of the patients treated with josamycin and for 68.7% of those treated with tetracycline. The results of this study confirm a high prevalence of asymptomatic Ct infection which may be correctly diagnosed by EIA performed on cervical and urethral samples. They also indicate that negative test results can be obtained by an appropriate antibiotic treatment.

Positive chlamydial serology and its effect on factors influencing outcome of IVF treatment

A retrospective study of 98 IVF treatment cycles from 49 couples has assessed the relationship between presence of antibodies to Chlamydia trachomatis and success with respect to fertilization, cleavage and pregnancy rate, both at nidation and term. No effect of prior infection on IVF outcome was noted.

Detection of Chlamydia trachomatis in urinary samples from women

With a mean age of 21 years 197 women at risk for an infection with Chlamydia trachomatis (CT) had a urinary sample (20 ml first-void urine, minimum 4 hours from prior mictuation) analysed with an enzyme immunoassay (IDEIA-III) for the detection of CT. They also had samples taken from both cervix and urethra for cultivation on McCoy's cells and testing with an enzyme immunoassay (Chlamydiazyme), plus verification of positive samples in the enzyme immunoassay (EIA) with monoclonal antibodies against CT. The urethral samples were compared against the urinary samples with regard to sensitivity and specificity in detecting CT. Women with a positive culture for CT and/or a positive verified EIA from either the cervix or the urethra, were regarded as "true" infections with CT. The prevalence of CT was 12.2%. The urinary EIA sample had a sensitivity of 84% whereas the urethral EIA sample had a sensitivity of 57%. The specificity was 98% and 100% for the urinary samples, and the urethral samples respectively. It is concluded that the urinary sample is superior to the urethral sample, and that the urinary sample could be used for screening programs, to detect CT among women.

Implications for persistent chlamydial infections of phagocyte-microorganism interplay

In vitro models of Chlamydia trachomatis inhibition by cytokines, human-monocyte derived macrophages (HMDM) and human polymorphonuclear leukocytes (HPMN) are discussed in an attempt to delineate the molecular basis of parasite-host cell interplay in persistent and chronic chlamydial infection. Interferon gamma (IFN) has been found to reversibly inhibit chlamydial growth at an early stage in the replicative cycle, while tumor necrosis factor (TNF) has a more profound effect on chlamydial growth resulting in production of aberrant reticulate bodies and enhancement of production of prostaglandin E2 (PGE2). Chlamydia trachomatis (serovar L2) replicate in HMDM while serovar K has been found to be restricted in these cells. Chlamydiae are killed by HPMN but the cell walls persist undegraded, inducing production of oxygen radicals which can be demonstrated to induce DNA strand scissions in HeLa target cells. Evidence is accumulating that chlamydia specific serum IgA antibodies may serve as a noninvasive serological marker for diagnosis of a number of acute and persistent Chlamydia trachomatis infections.

Inhibition of growth of Chlamydia trachomatis by tumor necrosis factor is accompanied by increased prostaglandin synthesis

Development of Chlamydia trachomatis (L2/434/Bu) in HEp-2 cells was inhibited by treatment of the cells with recombinant human alpha tumor necrosis factor (TNF). In the infected cultures that were treated with TNF, high concentrations of prostaglandin E2(PGE2) were detected, exceeding by far the concentrations found in TNF-treated but uninfected cells or in infected cells that were not treated with TNF. PGE2 levels increased gradually for 2 days after infection. Raising the tryptophan concentration in the culture medium, which reversed the inhibition of chlamydial replication by TNF, also blocked the increase in PGE2 formation. However, neutralizing antibodies to beta interferon, which also interfered with the antichlamydial effect of TNF, did not decrease PGE2 formation. Excessive formation of PGE2 by cells infected with chlamydiae and treated by TNF might be related to some of the complications associated with chlamydial infection.

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.

A polymerase chain reaction (PCR) protocol for the specific detection of Chlamydia spp

The polymerase chain reaction is an in vitro procedure for primer-directed enzymatic amplification of specific template nucleic acid sequences. This technique was used to detect and differentiate Chlamydia trachomatis and Chlamydia psittaci in laboratory samples of infected McCoy cells. The polymerase chain reaction was shown to be both sensitive, detecting in the order of one chlamydial DNA molecule in 10(5) cells, and specific. No cross reaction (amplified product) was detected when a variety of mammalian cell and bacterial DNAs were used as template with the Chlamydia-specific oligonucleotide primers.

Enzyme immunoassay to determine exposure to Chlamydia pneumoniae (strain TWAR)

Recent studies suggest that a group of Chlamydia strains known as TWAR, which are now proposed to be a new species called Chlamydia pneumoniae, may be a frequent cause of respiratory disease in the United States and many other countries. Current serotesting methods do not allow rapid screening of large numbers of samples to distinguish C. trachomatis exposure from C. pneumoniae exposure. We developed an enzyme immunoassay to decrease cross-reactivity between immunoglobulin G antibodies reactive with C. trachomatis and C. pneumoniae. Elementary bodies of C. trachomatis or C. pneumoniae were treated with a detergent-chelating solution to decrease the reactivity of the common lipopolysaccharide antigens. Sera from four groups of patients, totaling 143 persons, were tested by this assay. The prevalences of titers of greater than or equal to 128 to C. trachomatis and C. pneumoniae, respectively, were as follows: (i) for 23 women seropositive for C. trachomatis by the microimmunofluorescence test, 21 (91%) and 18 (78%); (ii) for 50 adult blood donors, 13 (26%) and 39 (78%); (iii) for 40 sexually transmitted disease clinic patients, 20 (50%) and 32 (80%); (iv) for 30 healthy children 5 to 7 years old, 0 (0%) and 8 (27%). Western blots (immunoblots) of each antigen corroborated the differential reactivity of C. trachomatis-positive, C. pneumoniae-negative and C. trachomatis-negative, C. pneumoniae-positive serum samples. Western blots of serum samples from rabbits immunized with either C. trachomatis or C. pneumoniae elementary bodies revealed at least two protein bands (30 and 80 kilodaltons) which appeared to represent unique C. pneumoniae antigens.

Reversion of the antichlamydial effect of tumor necrosis factor by tryptophan and antibodies to beta interferon

Human recombinant tumor necrosis factor-alpha (TNF-alpha) inhibited the growth of Chlamydia trachomatis (L2/434/Bu) in HEp-2 cells. The effect was synergistic with that of gamma interferon (IFN-gamma). TNF-induced resistance to chlamydiae could be blocked with cycloheximide, suggesting that it involves the function of some induced proteins. Tryptophan degradation was enhanced in the TNF-treated cells and was much further increased when the cells were treated with both TNF and IFN-gamma at concentrations at which IFN-gamma by itself had very little effect. Antibodies to IFN-beta blocked the augmentation of tryptophan degradation by TNF and decreased but did not fully eliminate the antichlamydial effect of TNF. Increased concentration of tryptophan in the growth medium (greater than 100 micrograms/ml) resulted in reversion of the antichlamydial effect of TNF. This study suggests that the inhibition of chlamydial growth by TNF is mediated partly through an autocrine function of IFN-beta which, in synergism with TNF, enhances the activity of a tryptophan-degrading enzyme(s) and partly by some other activities of TNF which can be blocked by tryptophan.

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.

Detecting Chlamydia trachomatis in men with urethritis: serology v isolation in cell culture

The accuracy of single serovar (L2) inclusion immunoperoxidase assay (IPA) to show serum IgG and IgA antibodies specific to chlamydiae was compared with culture for Chlamydia trachomatis to diagnose chlamydial infection in 73 men with acute urethritis. C trachomatis only was isolated from 18 (25%), Neisseria gonorrhoeae only from 17 (23%), and both organisms from six (8%). Thus 24 (33%) yielded chlamydiae. Assays based on IgG antibodies to chlamydiae at a titre of 1/64 or more showed high sensitivity (96%) and a good negative predictive value (80%), but low specificity (13%) and agreement (48%) compared with culture. IgG antibodies to chlamydiae at a titre of 1/128 or more showed lower sensitivity (75%) but higher specificity (72%), negative predictive value (79%), and agreement (73%). IgA antibodies to chlamydiae at a titre of 1/8 or more showed a sensitivity of 88%, specificity of 72%, negative predictive value of 88%, and agreement of 79%. An appreciable (fourfold or more) decrease in IgA and IgG titres was observed in most (10) of the 15 men from whom second blood samples were obtained one to two years after treatment. Measuring specific IgA and IgG antibodies to chlamydiae by IPA may serve as a useful complementary test for diagnosing and following up patients with urethritis.

Chlamydial infection and male infertility: an epidemiological study

Chlamydia-positive genitourinary infections are common causes of male and female infertility. Semen abnormalities are often associated with Chlamydia infections. A large population of male patients, admitted to our clinic for genitourinary infection, were examined for genitourinary pathogens, including Chlamydia, and for semen abnormalities. There were higher abnormalities semen in Chlamydia-infected patients than either non-Chlamydia-infected or healthy controls. Chlamydia therapy by antimicrobial agents improved semen characteristics. Chlamydia infection contributes to seminal fluid abnormalities and probably to male infertility. A search for chlamydial infection is warranted whenever semen abnormalities are noted. An antimicrobial therapy improves semen quality when effective in eradicating Chlamydia.

Inhibition of Chlamydia trachomatis replication in HEp-2 cells by human monocyte-derived macrophages

Monocytes (M) and macrophages are important components of the immune response to foreign agents. Using an in vitro system, we studied the influence of human M and M-derived macrophages (MdM) on the replication of Chlamydia trachomatis (L2/434) in HEp-2 cells. M or MdM were added to infected cells at a ratio of 4:1, and the resultant chlamydial yield was evaluated in one-step growth experiments. Chlamydial DNA production was evaluated by dot hybridization. Both M and MdM reduced chlamydial yield and DNA production, but the reductions caused by MdM were more pronounced. Electron microscopy showed that while control HEp-2 cells at 48 h postinfection contained large inclusions in which most particles were elementary bodies, the infected HEp-2 cells exposed to MdM contained small vacuoles with abnormal reticulate bodies and very few typical elementary bodies. Separation of the MdM from the HEp-2 cells by a membrane reduced the inhibitory effect of the MdM relative to that of MdM in direct contact with the infected cells. Addition of tumor necrosis factor antibodies to C. trachomatis-infected HEp-2 cells exposed to MdM (either in direct contact or separated by a membrane from the infected cells) reduced the inhibition of chlamydial DNA production. These data suggest the possibility that MdM may modulate C. trachomatis replication in vivo.

Inhibition of Chlamydia trachomatis growth by recombinant tumor necrosis factor

Purified human recombinant tumor necrosis factor (rTNF) alpha inhibited the growth of Chlamydia trachomatis (L2/434/Bu) in HEp-2 cell cultures. The inhibition of C. trachomatis yield could be achieved even when the rTNF alpha (200 ng/ml) was added up to 12 h after infection. The effect of rTNF alpha on chlamydial infection was synergistic with that of gamma interferon.

Chlamydia specific IgG and IgA antibodies in women with obstructive infertility as determined by immunoblotting and immunoperoxidase assays

The prevalence rate of IgG and IgA antibodies to Chlamydia was analyzed in 50 women with laparoscopy-verified tubal infertility and in 50 age-matched control women by single serovar (L2) inclusion immunoperoxidase assay (IPA) and by immunoblotting technique (IB). Women with tubal infertility had significantly (p less than 0.001) elevated IPA Chlamydia IgG antibody titer greater than or equal to 128 and greater than or equal to 256 than controls (64% vs 16%. Odds ratios = 9.3 and 50% vs 10%, Odds ratio = 9 respectively). The prevalence rate of IPA IgA antibody titer (greater than or equal to 16) to Chlamydia was also significantly higher (p less than 0.001) in women with tubal infertility than controls (48% vs 8%, Odds ratio = 10.6). Antibodies to at least 19 chlamydial structural polypeptides ranging in molecular weight from 30 kD to 204 kD, were detected by the IB technique in the IPA seropositive sera. Antibodies to 57-60 kD were detectable in almost all the IPA IgG and IgA seropositive sera. The prevalence rate of IgG antibody to 57 kD-60 kD was significantly higher in women with obstructive infertility than healthy woman (84% vs. 56% p less than 0.01; Odds ratio = 3.8). More significantly, higher differences to 57-60 kD polypeptide were found in the case of IgA between the infertile women and controls (52% vs. 10%, p less than 0.001; Odds ratio = 9.7). The significance of IPA and IB technique for screening of infertile women is discussed.

Trachoma through history

History of 'ophthalmia' is as old as history itself; no race or community is immune to it. There were times when blinding trachoma took a form of disastrous epidemics. The historical and recent literature are reviewed in this paper.

Immunomodulation and Chlamydia: immunosuppression and the protective immune response to C. psittaci in mice

Mice immunized intramuscularly with a low dose, viable inoculum of C. psittaci survived an otherwise lethal intraperitoneal challenge with the homologous chlamydial strain. Immunized animals were not protected from intraperitoneal challenge by the unrelated pathogen, Listeria monocytogenes. Spleen cells from animals that exhibited protective immunity were suppressed in their proliferative responses to mitogens or chlamydial antigen in an in vitro blastogenic assay. This suppression was transferable to normal spleen cells by adding irradiated cells from immunized animals to normal cell populations. The degree of normal cell blastogenic suppression was dependent on the ratio of irradiated immune to normal cells present in the assay medium. Suppression of humoral responses was demonstrated in vivo. Immunized animals were incapable of producing antibody secreting cells to sheep red blood cells after an intraperitoneal inoculation of SRBC. Unimmunized animals produced a significant number of plaque forming cells as measured by a direct plaque forming cell assay. Lymphokine activity was not impaired in spleen cells from mice that exhibited other manifestations of suppression. Taken together, these data provide evidence to indicate that the induction of suppression may not correlate with increased pathogenesis, but rather be closely associated with protective immunity. Data also provide circumstantial evidence to indicate that lymphokine induction may be important in the development of protective immunity to C. psittaci in the mouse.

Correlation between chlamydia infection and clinical evaluation, vaginal wet smear, and cervical swab test in female adolescents

Vaginal wet smear, endocervical swab test, gynecologic examination, and history were investigated in 148 healthy female adolescents. Cultures for Chlamydia trachomatis were obtained from all patients. The overall prevalence was 19/148 (13%). No significant correlation was found between chlamydia infection and any of the parameters investigated in the wet smear. Results of swab test or history showed no discrimination between young women with cultures positive for C. trachomatis and those with cultures negative for C. trachomatis. Chlamydia was found in 32% of patients when the gynecologic examination showed signs of infection and in 10% when no signs of infection were seen (p less than 0.025). Thirteen of the 19 (70%) adolescents with chlamydia infections had no signs of infection. We conclude that neither swab test, vaginal wet smear, nor the history of the patient can give conclusive evidence of a chlamydial infection. Detection of C. trachomatis in this population can be done only by culture or other specific methods.

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.