Persistent Chlamydia Trachomatis Research Articles

Yinjia pill inhibits persistent Chlamydia trachomatis infection.

Yinjia pill inhibits persistent Chlamydia trachomatis infection.

C-Myc plays a key role in IFN-γ-induced persistence of Chlamydia trachomatis.

Chlamydia trachomatis (Ctr) can persist over extended times within their host cell and thereby establish chronic infections. One of the major inducers of chlamydial persistence is interferon-gamma (IFN-γ) released by immune cells as a mechanism of immune defence. IFN-γ activates the catabolic depletion of L-tryptophan (Trp) via indoleamine-2,3-dioxygenase (IDO), resulting in persistent Ctr. Here, we show that IFN-γ induces the downregulation of c-Myc, the key regulator of host cell metabolism, in a STAT1-dependent manner. Expression of c-Myc rescued Ctr from IFN-γ-induced persistence in cell lines and human fallopian tube organoids. Trp concentrations control c-Myc levels most likely via the PI3K-GSK3β axis. Unbiased metabolic analysis revealed that Ctr infection reprograms the host cell tricarboxylic acid (TCA) cycle to support pyrimidine biosynthesis. Addition of TCA cycle intermediates or pyrimidine/purine nucleosides to infected cells rescued Ctr from IFN-γ-induced persistence. Thus, our results challenge the longstanding hypothesis of Trp depletion through IDO as the major mechanism of IFN-γ-induced metabolic immune defence and significantly extends the understanding of the role of IFN-γ as a broad modulator of host cell metabolism.

The role of tryptophan in Chlamydia trachomatis persistence.

Chlamydia trachomatis (C. trachomatis) is the most common etiological agent of bacterial sexually transmitted infections (STIs) and a worldwide public health issue. The natural course with C. trachomatis infection varies widely between individuals. Some infections clear spontaneously, others can last for several months or some individuals can become reinfected, leading to severe pathological damage. Importantly, the underlying mechanisms of C. trachomatis infection are not fully understood. C. trachomatis has the ability to adapt to immune response and persist within host epithelial cells. Indoleamine-2,3-dioxygenase (IDO) induced by interferon-gamma (IFN-γ) degrades the intracellular tryptophan pool, to which C. trachomatis can respond by converting to a non-replicating but viable state. C. trachomatis expresses and encodes for the tryptophan synthase (TS) genes (trpA and trpB) and tryptophan repressor gene (trpR). Multiple genes interact to regulate tryptophan synthesis from exogenous indole, and persistent C. trachomatis can recover its infectivity by converting indole into tryptophan. In this review, we discuss the characteristics of chlamydial infections, biosynthesis and regulation of tryptophan, the relationship between tryptophan and C. trachomatis, and finally, the links between the tryptophan/IFN-γ axis and C. trachomatis persistence.

C-reactive protein as a marker of persistent Chlamydia trachomatis infection is not associated with tubal factor infertility-an independent clinical validation study.

STUDY QUESTIONDoes C-reactive protein (CRP), as a marker of persisting low-grade inflammation, identify Chlamydia trachomatis IgG antibody test (CAT)-positive women who are at the highest risk for tubal factor infertility (TFI)?SUMMARY ANSWERNo association was found between slightly elevated CRP (seCRP) levels and TFI in our CAT-positive patient population.WHAT IS KNOWN ALREADYIn the fertility work-up, CAT is used to estimate the risk for TFI and to select high-risk patients for additional invasive diagnostic procedures (e.g. hysterosalpingography and laparoscopy). However, a high number of false positives exist among CAT-positive patients. In a previous study, it has been suggested that women with TFI may be identified more accurately when combining CAT with CRP, a marker for persistent low-grade inflammation.STUDY DESIGN, SIZE, DURATIONOur original retrospective cohort consisted of 887 consecutive female patients who visited the fertility clinic of a tertiary care centre between 2007 and 2015. All CAT-positive women who underwent laparoscopy (as the reference test for evaluation of tubal function) and who had not undergone previous pelvic surgery were included in the study. CRP was determined in spare serum samples, and medical data was obtained by chart review.PARTICIPANTS/MATERIALS, SETTING, METHODSA total of 101 women (11.4%) were CAT-positive, and 64 of these 101 women (7.2%) met all inclusion criteria. CAT was performed with an ELISA. TFI was assessed by laparoscopy and strictly defined as extensive peri-adnexal adhesions and/or distal occlusion of at least one tube. In spare sera, CRP was performed with a high-sensitivity CRP ELISA, and CRP levels between 3 and 10 mg/L were defined as positive. Analyses were corrected for BMI, endometriosis and smoking.MAIN RESULTS AND THE ROLE OF CHANCEThere was no statistically significant association between seCRP level and TFI after adjusting for BMI, endometriosis and smoking (odds ratio 1.0; 95% CI 0.3–3.3; n = 64).LIMITATIONS, REASONS FOR CAUTIONOur retrospective study had a small sample size due to a low CAT-positivity rate and a conservative clinical policy with regard to invasive diagnostic testing. Additionally, CRP levels were only measured once, while they may change throughout the menstrual cycle and in time.WIDER IMPLICATIONS OF THE FINDINGSContrary to previous findings, our results show CRP is not suitable as a marker of persistent low-grade inflammation in CAT-positive women. Other inflammatory markers and immunogenetic host factors should be studied on their clinical validity and utility to improve non-invasive risk assessment for TFI in the fertility work-up.STUDY FUNDING/COMPETING INTEREST(S)This work was partially supported by the European EuroTrans-Bio Grant [Reference number 110012 ETB] and the Eurostars grant (E!9372). S.A.M., a full-time employee of Amsterdam University Medical Centres location VUMC (0.56 fte) and the Maastricht University Medical Center (0.44 fte), is the founder (2011) and CEO of TubaScan Ltd, a spin-off company, Dept. of Medical Microbiology and Infection Prevention, Amsterdam UMC, location VUmc, Amsterdam, the Netherlands. S.O. and E.F.v.E. at the time of conducting this research had a partial appointment at TubaScan Ltd.

An in vitro model of azithromycin-induced persistent Chlamydia trachomatis infection.

Single-dose azithromycin is recommended for treating Chlamydia trachomatis infections. Here, we established an in vitro cell model of azithromycin-induced persistent infection. Azithromycin inhibited the replication of C. trachomatis in a dose-time-dependent manner. Electron microscopy indicated that small inclusions in the induced model contained enlarged, aberrant and non-infectious reticulate bodies. RT-PCR showed that C. trachomatis still has the ability to express the unprocessed 16S rRNA gene in the model and that C. trachomatis recovered after the removal of azithromycin with a peak recovery time of 24 h. The mutations in 23S rRNA, L4 and L22 genes were not found in persistent infection, and qRT-PCR analysis showed that the relative expression level of euo in azithromycin treated infection was upregulated while omcB was downregulated. In summary, this study provides a novel in vitro cell model to examine the characteristics of azithromycin-induced persistent infection and contribute to the development of treatments for C. trachomatis infection.

Differences in Rab protein expressions in McCoy cells with acute versus persistent Chlamydia trachomatis infection

Objective To investigate differences in Rab protein expressions in McCoy cells with acute versus persistent Chlamydia trachomatis (Ct)infection. Methods Cultured McCoy cells were infected with different amounts(400, 500, 550 μl/well)of Ct strain D suspensions , then cultured with the medium containing 100 U/ml penicillin G(persistent Ct infection groups)or that without penicillin G (acute Ct infection groups). Ctuninfected McCoy cells receiving no penicillin G treatment served as the blank control group, and those receiving penicillin G treatment as the penicillin group. After 48-hour culture, McCoy cells were lysed, proteins were collected, and total RNA was extracted from the cells. Enzyme-linked immunosorbent assay (ELISA)was conducted to measure protein levels of Rab4A, Rab6A, Rab10, Rab11A and Rab14, and fluorescence-based quantitative PCR to quantify mRNA expressions of Rab4A and Rab14 (expressed as 2-ΔΔCt). Results Protein levels of Rab4A, Rab6A, Rab10, Rab11A and Rab14 were all significantly lower in the acute than in the persistent Ct infection groups (all Z = 3.621, P 0.05). In addition, the expressions of Rab4A and Rab14 mRNAs were consistent with those of their proteins in these groups. Conclusion The transcriptional and expression levels of Rab proteins are higher in McCoy cells persistently infected with Ct than in those acutely infected with Ct. Key words: Chlamydia trachomatis; Chlamydia infections; rab GTP-binding proteins; Acute infection; Persistent infection; McCoy cells

A small-molecule compound belonging to a class of 2,4-disubstituted 1,3,4-thiadiazine-5-ones inhibits intracellular growth and persistence of Chlamydia trachomatis.

Chlamydia trachomatis is one of the most common sexually transmitted pathogens in the world and often causes chronic inflammatory diseases that are insensitive to antibiotics. The type 3 secretion system (T3SS) of pathogenic bacteria is a promising target for therapeutic intervention aimed at bacterial virulence and can be an attractive alternative for the treatment of chronic infections. Recently, we have shown that a small-molecule compound belonging to a class of 2,4-disubstituted 1,3,4-thiadiazine-5-ones produced through the chemical modification of the thiohydrazides of oxamic acids, designated CL-55, inhibited the intracellular growth of C. trachomatis in a T3SS-dependent manner. To assess the feasibility of CL-55 as a therapeutic agent, our aim was to determine which point(s) in the developmental cycle CL-55 affects. We found that CL-55 had no effect on the adhesion of elementary bodies (EBs) to host cells but significantly suppressed EB internalization. We further found that CL-55 inhibited the intracellular division of reticulate bodies (RBs). An ultrastructural analysis revealed loss of contact between the RBs and the inclusion membrane in the presence of CL-55. Finally, we found that our T3SS inhibitor prevented the persistence of Chlamydia in cell culture and its reversion to the infectious state. Our findings indicate that our T3SS inhibitor may be effective in the treatment of both productive and persistent infections.

O15.6 Impact of the lng-ius on cervical persistence ofchlamydia trachomatisand vaginal microbiota in a baboon model

Introduction Alterations in vaginal microbiota associated with intrauterine contraception may impact host susceptibility to sexually transmitted infection. We evaluated the effect of the levonorgestrel intrauterine system (LNG-IUS) on cervical persistence of Chlamydia trachomatis (CT) in a baboon model and whether CT persistence was correlated with vaginal microbial community structure. Methods 20 wild caught female olive baboons ( Papio abubis ) were randomly assigned to receive either LNG-IUS and CT inoculation (n = 8), LNG-IUS and sham inoculum (n = 2), CT inoculation alone (n = 8), or sham inoculation (n = 2). Animals were acclimated to the LNG-IUS for 24 weeks after which animals were cervically inoculated once weekly for 5 weeks. Vaginal swabs were collected weekly for microbiome analysis by 16S rRNA-encoding gene sequence analysis. Presence of CT in the cervical epithelium was confirmed with weekly nucleic acid amplification testing (NAAT) and culture. Results Use of the LNG-IUS was significantly associated with positive CT culture (p = 0.04) but not NAAT (p = 0.07). Median time to cervical clearance of CT as detected by NAAT was 12.5 days (range 5–16) for LNG-IUS animals in comparison to 7 days (range 3–10) for non-implanted animals (p = 0.14). Similarly, median time to cervical clearance of CT by culture was 12 days (range 5–15) for LNG-IUS animals and 5 days (range 1–10) for non-implanted animals (p = 0.05). We did not detect significant within group differences between vaginal microbial community structure at baseline and following LNG-IUS insertion, CT inoculation, or LNG-IUS and CT in combination. Conclusions Use of the LNG-IUS was associated with a trend towards cervical persistence of CT in a baboon model. However, this persistence is not explained by alterations in vaginal microbial communities. Disclosure of interest statement The authors have no disclosures to report.

Association of the in vitro susceptibility of clinical isolates of chlamydia trachomatis with serovar and duration of antibiotic exposure.

The presence of persistent Chlamydia trachomatis infection after treatment does not always correlate with in vitro susceptibility testing. The in vitro minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of azithromycin, clarithromycin, roxithromycin, doxycycline, tetracycline, ofloxacin, and penicillin were tested against 61 clinical isolates of C. trachomatis on 6 serovars, and the MIC/MBC of azithromycin and ofloxacin at different points in time after antibiotic administration to infected cultures. Of the 7 antibiotics tested, clarithromycin showed the greatest activity against C. trachomatis isolates with MIC90 of 0.032 μg/mL and MBC90 of 0.064 μg/mL, followed by doxycycline with MIC90 0.064 μg/mL and MBC90 0.064 μg/mL, and azithromycin with MIC90 0.160 μg/mL and MBC90 0.320 μg/mL. Azithromycin had roughly the same MIC50 values (0.08 μg/mL) as the other serovars isolates tested, and other antibiotics showed a 2- to 4-fold difference in MICs50 between serovars. In addition, an increase in the azithromyin MIC was observed by 8 hours and the ofloxacin MIC by 16 hours. At 24 hours, the azithromycin MICs were greater than 40 μg/mL and ofloxacin MICs were greater than 64 μg/mL. The current data demonstrated that the antimicrobial susceptibility of C. trachomatis was influenced by both the serovar type and the duration of exposure to antibiotics in infected cultures.

High prevalence of hpv multiple genotypes in women with persistent chlamydia trachomatis infection.

BackgroundChlamydia trachomatis interaction with HR-HPV types has highlighted a central role in cervical cancer development. The aim of this study was to investigate HPV prevalence and genotypes distribution in women at risk for C. trachomatis infection and negative for intraepithelial lesion or malignancy.Methods1071 cervical swabs were tested for C. trachomatis by Real Time PCR and genotyping by ompA gene sequencing. Additionally, a quantitative Real time-PCR was performed to assess the expression of the C. trachomatis Hsp60–encoding gene (Ct604 portion), linked to a persistent status of infection. HPV infection and genotypes was investigated in C. trachomatis positive women using Luminex technology.ResultsC. trachomatis infection was detected in 53 out of 1071 (4.5%) samples, of which the 53% resulted positive for Hsp60 gene expression. The overall prevalence of HPV infection in C. trachomatis positive samples was of 60.4% (32/53): in 37.5% of samples was present a single genotype, while multiple genotypes infections were found in the 62.5% of them. Among women with a C. trachomatis chronic infection, 68% were HPV co-infected and the 79% showed multiple genotypes. Should be noted that levels of C. trachomatis Hsp60 expression in HPV co-infected women were significantly lower compared to women infected only with C. trachomatis. The C. trachomatis serotype F was found in the majority of samples, independently of HPV infection.ConclusionsA high prevalence of HPV multiple infections have been found in young women affected with a C. trachomatis chronic infection. These observations suggested that the expression of CHSP60-1, interfering with both apoptotic and cellular senescence pathways, may promote a favourable local microenvironment for HPV infection.

Host immune responses after hypoxic reactivation of IFN-γ induced persistent Chlamydia trachomatis infection

Genital tract infections with Chlamydia trachomatis (C. trachomatis) are the most frequent sexually transmitted disease worldwide. Severe clinical sequelae such as pelvic inflammatory disease (PID), tubal occlusion, and tubal infertility are linked to inflammatory processes of chronically infected tissues. The oxygen concentrations in the female urogenital tract are physiologically low and further diminished (0.5–5% O2, hypoxia) during an ongoing inflammation. However, little is known about the effect of a low oxygen environment on genital C. trachomatis infections. In this study, we investigated the host immune responses during reactivation of IFN-γ induced persistent C. trachomatis infection under hypoxia. For this purpose, the activation of the MAP-kinases p44/42 and p38 as well as the induction of the pro-inflammatory cytokines IL-1β, IL-6, IL-8, and MCP-1 were analyzed. Upon hypoxic reactivation of IFN-γ induced persistent C. trachomatis infection, the phosphorylation of the p44/42 but not of the p38 MAP-kinase was significantly diminished compared to IFN-γ induced chlamydial persistence under normoxic condition. In addition, significantly reduced IL-6 and IL-8 mRNA expression levels were observed for reactivated Chlamydiae under hypoxia compared to a persistent chlamydial infection under normoxia. Our findings indicate that hypoxia not only reactivates IFN-γ induced persistent C. trachomatis infections resulting in increased bacterial growth and progeny but also dampens inflammatory host immune signaling responses that are normally observed in a normoxic environment.

Polymorphism of HLA-D QA1 alleles in Chinese Han patients with persistent Chlamydia trachomatis genital infection

Objective To analyze the association of HLA-DQA1 gene polymorphism with persistent Chlamydia trachomatis genital infection.Methods Blood samples were collected from 80 patients with persistent genital Chlamydial infection,80 patients with common genital Chlamydial infection (who tested negative for Chlamydia trachomatis after one course of standard systemic treatment) and 80 normal human controls.HLA-DQA1 alleles were genotyped by PCR followed by gene sequencing.Results The frequency of HLA-DQA1*0102 allele and HLA-DQA1*0501 allele was 22.5％ and 5.0％ respectively in patients with persistent genital Chlamydial infection,5％ and 20％ respectively in those with common genital Chlamydial infection,2.5％ and 17.5％ respectively in normal human controls.Compared with the patients with common genital Chlamydial infection and controls,the patients with persistent genital Chlamydial infection had a higher frequency of HLA-DQA1*0102 (x2 =14.6286,P ＜ 0.001 ),but a lower frequency of DQA1*0501 (x2 =6.2598,P ＜ 0.05).Conclusions HLA-DQA1*0102 allele may be a susceptible gene or closely linked with the susceptible genes of persistent genital Chlamydial infection.HLA-DQA1*0501 allele may have protective effects against persistent genital Chlamydial infection.

Persistent Chlamydia trachomatis Infection of HeLa Cells Mediates Apoptosis Resistance through a Chlamydia Protease-Like Activity Factor-Independent Mechanism and Induces High Mobility Group Box 1 Release

Intracellular persistence of Chlamydia trachomatis has been implicated in the development of chronic infection that can result in pelvic inflammatory disease and tubal sterility. By inhibition of host cell apoptosis, chlamydiae have evolved a strategy to maintain the intracellular environment for replication and persistence. Both antiapoptotic host cell-derived factors and the chlamydial protease-like activity factor (CPAF) are involved in Chlamydia-mediated apoptosis resistance. Here, we show that in HeLa cells infected with gamma interferon (IFN-γ)-induced persistent C. trachomatis serovar D, the expression of CPAF is downregulated, and proapoptotic protease substrates are not cleaved. Persistent infection protected HeLa cells from apoptosis when they were exposed to staurosporine. Small-interfering RNA-mediated inhibition of myeloid cell leukemia 1 (Mcl-1) protein upregulation sensitized persistently infected cells for apoptosis. The inhibitor of apoptosis protein 2 (IAP-2) seems not to be relevant in this context because IAP-2 protein was not induced in response to IFN-γ treatment. Although apoptosis was inhibited, persistent infection caused cell membrane disintegration, as measured by the increased release of cytokeratin 18 from HeLa cells. Moreover, persistently infected cells released significantly increased amounts of high mobility group box 1 (HMGB1) protein which represents a proinflammatory damage-associated pattern molecule. The data of this study suggest that cells infected with persistent C. trachomatis are protected from apoptosis independently of CPAF but may promote chronic inflammation through HMGB1 release.

Analysis of modulated gene expression in a model of Interferon-γ-induced persistence of Chlamydia trachomatis in HEp-2 cells

Background Chlamydia trachomatis is an important pathogen, being the commonest sexually transmitted bacterial disease in the Western world and is also implicated in a number of acute and chronic diseases. Persistent infections of C. trachomatis are particularly associated with chronic infections, which although eliciting an immune response, result in tissue damage leading to complications such as pelvic inflammatory disease. Interferon (IFN)-γ is known to induce persistent infections of C. trachomatis both in vitro and in vivo. Methods A model of IFN-γ-induced persistence containing aberrant inclusions of C. trachomatis was developed in the HEp-2 cell line. Morphological changes to inclusions were assessed by fluorescence immunocytochemistry and transcript levels determined by Real-Time RT-PCR. To assess infectivity of C. trachomatis in an IFN-γ-induced persistent state, cultures containing aberrant inclusions were inoculated onto fresh HEp-2 monolayers. Results IFN-γ induced aberrant inclusion formation at 0.01 ng/ml. Doses from 0.05 to 100 ng/ml did not significantly increase numbers of aberrant inclusions, and some normal inclusions were observed at the highest dose of IFN-γ. Transfer of IFN-γ-treated C. trachomatis onto fresh cultures confirmed the infectivity of these cultures. Real-Time RT-PCR identified apparent increased expression of the C. trachomatis heat-shock response genes ct604 and ct755 at 96-h post-infection. However comparisons with control cultures suggest that this more likely reflects a failure to down regulate gene expression as observed in untreated cultures. Conclusions These data show that whereas IFN-γ induces aberrant inclusion formation, many normal inclusions are still observed at high doses of IFN-γ, and that the infectivity of such cultures is presumably from these. Transcriptional changes observed in response to IFN-γ suggest a failure of the C. trachomatis life cycle in response to IFN-γ, however IFN-γ-induced transcriptional changes may be masked by the presence of normal inclusions. The implications of these observations in relation to models of persistence of C. trachomatis are discussed.

Expedited Partner Therapy for Adolescents Diagnosed with Chlamydia or Gonorrhea: A Position Paper of the Society for Adolescent Medicine

Expedited Partner Therapy for Adolescents Diagnosed with Chlamydia or Gonorrhea: A Position Paper of the Society for Adolescent Medicine

Multiple site sampling does not increase the sensitivity of Chlamydia trachomatis detection in infertility patients

Persistent Chlamydia trachomatis infections are associated with tubal pathology. We studied whether sampling from multiple sites would increase the identification of the infections. Prospective cohort study. Tertiary care facility. Two hundred two infertile women. Smears were taken from the cervix, urethra, high vagina, fimbriae and the Douglas cavity. Blood samples were collected and tubal patency was assessed by pertubation with lipiodol and methylene blue. Detection of C. trachomatis DNA, detection of IgA and IgG antibodies against C. trachomatis, and antibodies against chlamydial heat-shock protein 60, tubal patency. Chlamydia trachomatis was detected in 2 of 202 patients, for an overall prevalence of 1%. In both patients PCR results were positive in the cervical, vaginal, and urethral specimens. Chlamydia trachomatis IgG, IgA, and chlamydial heat-shock protein 60 IgG were significantly more prevalent in women with distal tubal pathology than in those without (26/40 [65.0%] vs. 16/162 [9.9%], 9/40 [22.5%] vs. 7/162 [4.3%], and 34/40 [85.0%] vs. 34/162 [21.0%]). Bacterial colonization was found in 1 of 202 samples from the Douglas cavity. Routine DNA testing for C. trachomatis should be confined to cervical sampling. The association between tubal pathology and seropositivity of IgG, IgA, and cHSP60 IgG was confirmed but did not add clinically valuable information during the diagnostic workup of infertility patients.

Human Leukocyte Antigen (HLA)-B, DRB1, and DQB1 Allotypes Associated with Disease and Protection of Trachoma Endemic Villagers

Trachoma remains the leading preventable infectious cause of blindness in developing countries. Human leukocyte antigen (HLA) associations with ocular disease severity and persistent Chlamydia trachomatis infection of Tanzanians living in trachoma-endemic villages were examined to determine possible protective candidate allotypes for vaccine development. Buccal swab scrapes were taken from subjects in the Trichiasis Study Group (TSG), which studied females only, and the Family Trachoma Study (FTS), which compared persistently infected probands who had severe disease with disease-free siblings and parents. DNA was purified for polymerase chain reaction sequence-specific oligonucleotide identification of HLA-DRB1, DQB1, and B allotypes. Infection was detected from conjunctival scrapes using a C. trachomatis-specific PCR-enzyme immunoassay for the MOMP-1 gene. In the TSG, DR*B11 (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.26-0.90; P=0.02) was significantly associated with lack of trichiasis, whereas HLA-B*07 (OR, 3.26; 95% CI, 1.42-7.49; P=0.004) and HLA-B*08 (OR, 5.12; 95% CI, 1.74-15.05; P=0.001) were associated with trichiasis. In addition, HLA-B*14 was significantly associated with inflammatory trachoma + follicular trachoma (OR, 3.76; 95% CI, 1.70-8.33; P=0.04). There were no significant allele frequencies for the FTS. The data suggest that HLA-DRB*11 may offer protection from trichiasis in trachoma hyperendemic villages. Complete allotype identification and designation of its respective protective CD4(+) T-cell antigens could provide a testable candidate vaccine for blindness prevention. Additionally, buccal swab DNA was sufficiently stable when acquired under harsh field conditions and stored long term in the freezer for low-resolution HLA typing.

Herpes simplex virus co-infection-induced Chlamydia trachomatis persistence is not mediated by any known persistence inducer or anti-chlamydial pathway

Several inducers of chlamydial persistence have been described, including interferon-gamma (IFN-gamma), IFN-alpha, IFN-beta, and tumour necrosis factor-alpha (TNF-alpha) exposure, and iron, amino acid or glucose deprivation. A tissue-culture model of Chlamydia trachomatis/herpes simplex virus type-2 (HSV-2) co-infection indicates that viral co-infection stimulates the formation of persistent chlamydiae. This study was designed to ascertain whether co-infection-induced persistence is mediated by a previously characterized mechanism. Luminex assays indicate that IFN-gamma, IFN-alpha, and TNF-alpha are not released from co-infected cells. Semiquantitative RT-PCR studies demonstrate that IFN-beta, IFN-gamma, indoleamine 2,3-dioxygenase, lymphotoxin-alpha and inducible nitric oxide synthase are not expressed during co-infection. These data indicate that viral-induced persistence is not stimulated by any persistence-associated cytokine. Supplementation of co-infected cells with excess amino acids, iron-saturated holotransferrin, glucose or a combination of amino acids and iron does not restore chlamydial infectivity, demonstrating that HSV-2-induced persistence is not mediated by depletion of these nutrients. Finally, inclusions within co-infected cells continue to enlarge and incorporate C(6)-NBD-ceramide, indicating that HSV-2 co-infection does not inhibit vesicular transport to the developing inclusion. Collectively these data demonstrate that co-infection-induced persistence is not mediated by any currently characterized persistence inducer or anti-chlamydial pathway. Previous studies indicate that HSV-2 attachment and/or entry into the host cell is sufficient for stimulating chlamydial persistence, suggesting that viral attachment and/or entry may trigger a novel host pathway which restricts chlamydial development.

Staining of Chlamydia trachomatis elementary bodies: A suitable method for identifying infected human monocytes by flow cytometry

Persistence of Chlamydia trachomatis ( C. trachomatis) in the joint is the most frequent cause of reactive arthritis following urogenital tract infection. The resulting changes of host cell antigen- and cytokine-expression are not precisely understood. We developed and evaluated a direct cytometric approach to visualize in vitro C. trachomatis-infected monocytes. Infectious elementary bodies (EBs) of C. trachomatis serovar K were labelled by incubation with 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester (CFSE). Afterwards, human peripheral blood monocytes were cultured with the CFSE-labelled EBs and analysed by flow cytometry. Real-time polymerase chain reaction (PCR) was used to demonstrate intracellular uptake and viability of CFSE-labelled C. trachomatis by the determination of gene expression. Labelling EBs with CFSE may become a valuable tool for studying the interaction between C. trachomatis and the host cell.

Serum antibody response to the heat shock protein 60 of Chlamydia trachomatis in women with developing cervical cancer

Objective The purpose of this study was to determine whether serum antibody response to the three versions of chlamydial heat shock protein 60 is associated with an increased risk for cervical cancer. Study design Women with cervical carcinoma were identified by linking the data files of three Nordic serum banks with cancer registries. Overall, 178 women with invasive cervical carcinoma were identified. For each case, the earliest prediagnostic serum sample was chosen, and three matched control subjects who were free of cancer at the time of the case diagnosis were selected randomly. Serum antibodies to the chlamydial heat shock protein 60 were measured by enzyme-linked immunosorbent assay and correlated with the risk of the subsequent development of cervical cancer. Results Antibodies to chlamydial heat shock protein 60–1 were associated with cervical squamous cell carcinoma among cases with long lag time (>3.5 years; odds ratio, 2.4; 95% CI, 1.1–5.1). Antibodies to chlamydial heat shock protein 60–2 or chlamydial heat shock protein 60–3 were not associated with cervical cancer risk. Conclusions The finding that chlamydial heat shock protein 60–1 antibodies are associated with an increased cervical cancer risk suggests that persistent Chlamydia trachomatis infection may contribute to cervical neoplasia.