Alveolar epithelial cells type II are major target cells for C. pneumoniae in chronic but not in acute respiratory infection

Pulmonary presence of Chlamydia pneumoniae is associated with acute and chronic infections. We show that unapparent chlamydial infection in four out of 31 chronic obstructive pulmonary disease (COPD) patients (12.9%) is characterized by a significant increase in infected alveolar epithelial cells type II (18.2 +/- 3.5% vs. 2.3 +/- 0.9; IHC/ISH) compared to a newly established model of acute chlamydial infection (ACIM) in vital lung specimens from pulmonary lobectomy. Expression of cHSP60 demonstrated pathogen viability and virulence in the ACIM. We conclude that target cells differ in acute and chronic chlamydial infection and suggest the ACIM as a novel tool to analyze the host-pathogen-interactions in acute respiratory infections.     

Mixed infections with <Emphasis Type="Italic">Chlamydia</Emphasis> and porcine epidemic diarrhea virus - a new <Emphasis Type="Italic">in vitro</Emphasis> model of chlamydial persistence

Background  

Chlamydiae induce persistent infections, which have been associated with a wide range of chronic diseases in humans and animals. Mixed infections with Chlamydia and porcine epidemic diarrhea virus (PEDV) may result in generation of persistent chlamydial infections. To test this hypothesis, an in vitro model of dual infection with cell culture-adapted PEDV and Chlamydia abortus or Chlamydia pecorum in Vero cells was established.     

Chlamydia trachomatis and Anti-MUC1 Serology and Subsequent Risk of High-Grade Serous Ovarian Cancer: A Population-Based Case–Control Study in Northern Sweden

BACKGROUND: Chlamydia trachomatis salpingitis causes inflammatory damage to the fallopian tube and could potentially cause initiation and progression of high-grade serous ovarian cancer (HGSC). Furthermore, C. trachomatis infection may stimulate mucin 1 (MUC1) protein production, possibly affecting anti-MUC1 antibody levels. The aim of this study was to examine if serology indicating past infection with C. trachomatis as well as anti-MUC1 production was associated with subsequent risk of HGSC. MATERIALS AND METHODS: In a prospective nested case–control study within the Northern Sweden Health and Disease Study and the Northern Sweden Maternity Cohort, the prevalence of chlamydial and anti-MUC1 antibodies was analyzed in blood samples drawn more than one year before diagnosis from 92 women with HGSC and 359 matched controls. Matching factors were age, date at blood draw, and sampling cohort. Plasma C. trachomatis IgG was analyzed using commercial micro-immunofluorescence test; chlamydial Heat Shock Protein 60 IgG (cHSP60) and anti-MUC1 IgG were analyzed with ELISA technique. RESULTS: The prevalence of C. trachomatis IgG and cHSP60 IgG antibodies, as well as the level of anti-MUC1 IgG was similar in women with HGSC and controls (16.3% vs. 17.0%, P = 0.87; 27.2% vs. 28.5%, P = 0.80; median 0.24 vs. 0.25, P = 0.70). Anti-MUC1 IgG and cHSP60 IgG levels were correlated (r = 0.169; P < 0.001). CONCLUSIONS: The findings of this prospective nested case–control study did not support an association between C. trachomatis infection, as measured by chlamydial serology, or anti-MUC1 IgG antibodies, and subsequent risk of HGSC.     

Role of cervical dendritic cell subsets,co-stimulatory molecules,cytokine secretion profile and beta-estradiol in development of sequalae to Chlamydia trachomatis infection

Background  

Chlamydia trachomatis infection of the female genital tract can lead to serious sequelae resulting in fertility related disorders. Little is known about the mechanism leading to Chlamydia induced pathology and factors responsible for it. As only some of the women develops reproductive disorders while majority of the women clears infection without any severe sequalae, mucosal immune response in women with or without fertility disorders was studied to identify factors which may lead to final clinical outcome of chlamydial infection.     

Host immune responses to chlamydial inclusion membrane proteins B and C in Chlamydia trachomatis infected women with or without fertility disorders

Background  

With an increase in the number of putative inclusion membrane proteins (incs) in chlamydial genomes, there is a need for understanding their contribution in host-pathogen interactions. Thus in this study we determined the host mucosal and peripheral immune responses to incs (IncB and IncC) of Chlamydia trachomatis (CT).     

Social and demographic predictors of no transport prior to premature cardiac death: United States 1999–2000

Background

There have been suggestions of an association between Chlamydia pneumoniae, chlamydial heat shock protein (Ch-hsp) 60 and human heat shock protein (h-hsp) 60 infection sero-status and development of secondary cardiovascular events. Patients with diabetes might be at higher risk since they are prone to infections. The objective of this study was to investigate prospectively the role of Chlamydia pneumoniae (CP), chlamydial heat shock protein (Ch-hsp) 60 and a possible intermediate role of human heat shock protein (h-hsp) 60 sero-status in the development of secondary cardiovascular disease (CVD) events in patients with coronary heart disease (CHD) under special consideration of diabetes mellitus.

Methods

Patients aged 30–70 undergoing an in-patient rehabilitation program after acute manifestation of coronary heart disease (International Classification of Disease, 9^th Rev. pos. 410–414) between January 1999 and May 2000 in one of two participating rehabilitation clinics in Germany were included in this analysis. Chlamydia pneumoniae (CP), chlamydial heat shock protein (Ch-hsp) 60 and human heat shock protein (h-hsp) 60 status at baseline were measured by serum immunoglobulin G and A antibodies. Secondary CVD events (myocardial infarction, stroke, and cardiovascular death) were recorded during a mean follow-up period of 33.5 months (response = 87%).

Results

Among the 1052 subjects 37.4% and 39.3% were sero-positive to CP IgA and IgG respectively, 22.2% were sero-positive to Ch-hsp 60 IgG and 8.4% were positive to h-hsp 60 IgG at baseline. During follow-up, secondary CVD events occurred among 71 (6.8%) participants. Occurrence of a secondary CVD event was more common among CP (IgA) and CP (IgG) sero-positive than among sero-negative patients (p-values 0.04 and 0.1, respectively). The risk of secondary CVD events was increased among patients with both a positive CP sero-status and diabetes compared to infection negative, non-diabetic patients and in general, sero-positivity added a hazard to diabetes. The interaction term between infection sero-status and diabetes was not statistically significant. We were not able to show an intermediate role of human heat shock protein (h-hsp) 60 sero-status in the development of secondary CVD events in patients with CHD.

Conclusion

Results from this cohort of 1052 patients with pre-existing CHD cannot exclude a possible moderate increase in risk of secondary CVD events among patients with a positive infection sero-status. However, our study showed no intermediate role of human heat shock protein (h-hsp) 60 sero-status in the development of secondary CVD events in patients with CHD. Larger studies or meta-analysis of multiple studies are needed to address the interaction between infection sero-status and diabetes with adequate power.     

Determination of chlamydial load and immune parameters in asymptomatic, symptomatic and infertile women

The regulation of immune response and chlamydial infectious load in the cervix of human females is largely unknown. Infectious load in terms of inclusion-forming units (IFUs) was determined by quantitative cultures in Chlamydia -positive women, in asymptomatic women, women with mucopurulent cervicitis (MPC) and women with fertility disorders (FD). CD4⁺, CD8⁺, CD14⁺ cells, myeloid and plasmacytoid dendritic cells (mDCs and pDCs) in the cervix were quantified by flow cytometry. Cervical cytokines, levels of β-estradiol and C-reactive protein (CRP) in serum and cervical immunoglobulin A antibody to chlamydial major outer membrane protein antigen, chlamydial heat shock protein 60 and 10 antigens were measured by an enzyme-linked immunosorbent assay. In asymptomatic women, chlamydial load showed significant positive correlations with CD4, mDCs, interleukin-12 (IL-12) and IL-2; however, negative correlations were found with CD8 and IL-8 levels. In women with MPC, chlamydial IFUs correlated positively with CD8, pDC number, IL-8, CRP and interferon-γ (IFN-γ). In women with FD, chlamydial load showed a significant positive correlation with the pDC number, IL-10 and estradiol level and a negative correlation with CD4 and IFN-γ. Overall, these results suggest that the interplay between chlamydial infectious load and host immune responses may be the deciding factor for the clinical condition presented during Chlamydia trachomatis infection.     

Primary and secondary immune responses of mucosal and peripheral lymphocytes during Chlamydia trachomatis infection

Chlamydia trachomatis infection is followed by the development of antigen-specific cell-mediated immunity, which is detectable as a positive lymphocyte proliferation response to the chlamydial major outer membrane protein (MOMP) antigen. To date, however, there have been no studies on the mucosal immune responses to chlamydial antigens. This study aimed to study the primary and secondary immune responses of cervical lymphocytes in response to the chlamydial antigen. Median proliferative responses were found to be significantly (P<0.05) higher in patients with chlamydial infections than in controls. The chlamydial MOMP induced significantly higher IL-6 and IL-10 and lower interferon-gamma (IFN-gamma) secretion in cervical lymphocytes of Chlamydia-positive women, resulting in a T helper 2 response. On stimulation of peripheral blood mononuclear cells (PBMC) obtained from Chlamydia-positive women with the chlamydial antigen, the median levels of IL-10, IL-12 and IFN-gamma were higher than in controls, but the differences were not significant. Our study suggests that the mucosal immune responses towards Chlamydia trachomatis are different from those of PBMCs and are more helpful in understanding the cytokine responses in the female genital tract during chlamydial infection.     

<Emphasis Type="Italic">Chlamydophila pneumoniae</Emphasis> derived from inclusions late in the infectious cycle induce aponecrosis in human aortic endothelial cells

Background  

Atherosclerosis is still the leading cause of death in the western world. Besides known risk factors studies demonstrating Chlamydophila pneumoniae (C. pneumoniae) to be implicated in the progression of the disease, little is known about C. pneumoniae infection dynamics. We investigated whether C. pneumoniae induce cell death of human aortic endothelial cells, a cell type involved in the initiation of atherosclerosis, and whether chlamydial spots derive from inclusions.     

<Emphasis Type="Italic">Chlamydia pneumoniae</Emphasis> induces aponecrosis in human aortic smooth muscle cells

Background  

The intracellular bacterium Chlamydia pneumoniae is suspected to play a role in formation and progression of atherosclerosis. Many studies investigated cell death initiation versus inhibition by Chlamydia pneumoniae in established cell lines but nothing is known in primary human aortic smooth muscle cells, a cell type among others known to be involved in the formation of the atherosclerotic plaque. Type of cell death was analyzed by various methods in primary aortic smooth muscle cells after infection with Chlamydia pneumoniae to investigate a possible pathogenic link in atherosclerosis.     

60-kDa heat shock protein of Chlamydia pneumoniae is a target of T-cell immune response

Inflammatory processes contribute to the pathogenesis and complications of atherosclerosis and coronary heart disease (CHD). Several findings indicate that chlamydial heat shock proteins (HSP) may represent a particularly strong antigenic stimulus, able to induce specific humoral (Ab) and T-cell-mediated immune responses (CMI) linking infection by Chlamydia pneumoniae (CP) to immuno-pathological sequelae such as atherosclerosis and CHD. We have here evaluated the ability of chlamydial recombinant (r) HSP60 and rHSP10 to induce specific immune responses in human peripheral blood lymphocytes and in murine models. rHSP60, but not rHSP10, was shown to induce proliferation and Interferon-gamma secretion in lymphocytes of randomly selected blood donors, as well as to generate and detect delayed-type hypersensitivity response in HSP60-vaccinated mice. Overall, the present study provides new hints to evaluate a previous exposition to CP using rHSP60 in humans. Thus the evaluation of specific HSP60 CMI response in healthy subject could be useful to monitor the reactivity to Chlamydia pneumoniae possibly providing a link to CHD pathologies.     

Chlamydia trachomatis,Chlamydial Heat Shock Protein 60 and Anti-Chlamydial Antibodies in Women with Epithelial Ovarian Tumors

OBJECTIVE: Chlamydia trachomatis (C. trachomatis) infection has been suggested to promote epithelial ovarian cancer (EOC) development. This study sought to explore the presence of C. trachomatis DNA and chlamydial heat shock protein 60 (chsp60) in ovarian tissue, as well as anti-chlamydial IgG antibodies in plasma, in relation to subtypes of EOC. METHODS: This cross-sectional cohort consisted of 69 women who underwent surgery due to suspected ovarian pathology. Ovarian tissue and corresponding blood samples were collected at the time of diagnosis. In ovarian tumor tissue, p53, p16, Ki67 and chsp60 were analyzed immunohistochemically, and PCR was used to detect C. trachomatis DNA. Plasma C. trachomatis IgG and cHSP60 IgG were analyzed with a commercial MIF-test and ELISA, respectively. RESULTS: Eight out of 69 women had C. trachomatis DNA in their ovarian tissue, all were invasive ovarian cancer cases (16.7% of invasive EOC). The prevalence of the chsp60 protein, C. trachomatis IgG and cHSP60 IgG in HGSC, compared to other ovarian tumors, was 56.0% vs. 37.2% P = .13, 15.4% vs. 9.3% P = .46 and 63.6% vs. 45.5% P = .33 respectively. None of the markers of C. trachomatis infection were associated with p53, p16 or Ki67. CONCLUSIONS: C. trachomatis was detected in invasive ovarian cancer, supporting a possible role in carcinogenesis of EOC. However, there were no statistically significant associations of chsp60 in ovarian tissue, or plasma anti-chlamydial IgG antibodies, with any of the subtypes of ovarian tumors.     

<Emphasis Type="Italic">Chlamydia trachomatis</Emphasis>responds to heat shock,penicillin induced persistence,and IFN-gamma persistence by altering levels of the extracytoplasmic stress response protease HtrA

Background  

Chlamydia trachomatis, an obligate intracellular human pathogen, is the most prevalent bacterial sexually transmitted infection worldwide and a leading cause of preventable blindness. HtrA is a virulence and stress response periplasmic serine protease and molecular chaperone found in many bacteria. Recombinant purified C. trachomatis HtrA has been previously shown to have both activities. This investigation examined the physiological role of Chlamydia trachomatis HtrA.     

Immunobiological Outcomes of Repeated Chlamydial Infection from Two Models of Within-Host Population Dynamics

Background

Chlamydia trachomatis is a common human pathogen that mediates disease processes capable of inflicting serious complications on reproduction. Aggressive inflammatory immune responses are thought to not only direct a person''s level of immunity but also the potential for immunopathology. With human immunobiology being debated as a cause of prevailing epidemiological trends, we examined some fundamental issues regarding susceptibility to multiple chlamydial infections that could have implications for infection spread. We argue that, compared to less-frequent exposure, frequent exposure to chlamydia may well produce unique immunobiological characteristics that likely to have important clinical and epidemiological implications.

Methods and Results

As a novel tool for studying chlamydia, we applied principles of modeling within-host pathogen dynamics to enable an understanding of some fundamental characteristics of an individual''s immunobiology during multiple chlamydial infections. While the models were able to reproduce shorter-term infection kinetics of primary and secondary infections previously observed in animal models, it was also observed that longer periods between initial and second infection may increase an individual''s chlamydial load and lengthen their duration of infectiousness. The cessation of short-term repeated exposure did not allow for the formation of long-lasting immunity. However, frequent re-exposure non-intuitively linked the formation of protective immunity, persistent infection, and the potential for immunopathology.

Conclusions

Overall, these results provide interesting insights that should be verified with continued study. Nevertheless, these results appear to raise challenges for current evidence of the development of long-lasting immunity against chlamydia, and suggest the existence of a previously unidentified mechanism for the formation of persistent infection. The obvious next goal is to investigate the qualitative impact of these results on the spread of chlamydia.     

Temporal proteomic profiling of Chlamydia trachomatis–infected HeLa‐229 human cervical epithelial cells

Chlamydia trachomatis is the leading causative agent of bacterial sexually transmitted infections worldwide which can lead to female pelvic inflammatory disease and infertility. A greater understanding of host response during chlamydial infection is essential to design intervention technique to reduce the increasing incidence rate of genital chlamydial infection. In this study, we investigated proteome changes in epithelial cells during C. trachomatis infection by using an isobaric tags for relative and absolute quantitation (iTRAQ) labeling technique coupled with a liquid chromatography‐tandem mass spectrometry (LC‐MS³) analysis. C. trachomatis (serovar D, MOI 1)–infected HeLa‐229 human cervical carcinoma epithelial cells (at 2, 4 and 8 h) showed profound modifications of proteome profile which involved 606 host proteins. MGST1, SUGP2 and ATXN10 were among the top in the list of the differentially upregulated protein. Through pathway analysis, we suggested the involvement of eukaryotic initiation factor 2 (eIF2) and mammalian target of rapamycin (mTOR) in host cells upon C. trachomatis infection. Network analysis underscored the participation of DNA repair mechanism during C. trachomatis infection. In summary, intense modifications of proteome profile in C. trachomatis–infected HeLa‐229 cells indicate complex host‐pathogen interactions at early phase of chlamydial infection.     

Multi locus sequence typing of <Emphasis Type="Italic">Chlamydiales</Emphasis>: clonal groupings within the obligate intracellular bacteria <Emphasis Type="Italic">Chlamydia trachomatis</Emphasis>

Background  

The obligate intracellular growing bacterium Chlamydia trachomatis causes diseases like trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Several serovars and genotypes have been identified, but these could not be linked to clinical disease or outcome. The related Chlamydophila pneumoniae, of which no subtypes are recognized, causes respiratory infections worldwide. We developed a multi locus sequence typing (MLST) scheme to understand the population genetic structure and diversity of these species and to evaluate the association between genotype and disease.     

Chlamydia muridarum Lung Infection in Infants Alters Hematopoietic Cells to Promote Allergic Airway Disease in Mice

Background

Viral and bacterial respiratory tract infections in early-life are linked to the development of allergic airway inflammation and asthma. However, the mechanisms involved are not well understood. We have previously shown that neonatal and infant, but not adult, chlamydial lung infections in mice permanently alter inflammatory phenotype and physiology to increase the severity of allergic airway disease by increasing lung interleukin (IL)-13 expression, mucus hyper-secretion and airway hyper-responsiveness. This occurred through different mechanisms with infection at different ages. Neonatal infection suppressed inflammatory responses but enhanced systemic dendritic cell:T-cell IL-13 release and induced permanent alterations in lung structure (i.e., increased the size of alveoli). Infant infection enhanced inflammatory responses but had no effect on lung structure. Here we investigated the role of hematopoietic cells in these processes using bone marrow chimera studies.

Methodology/Principal Findings

Neonatal (<24-hours-old), infant (3-weeks-old) and adult (6-weeks-old) mice were infected with C. muridarum. Nine weeks after infection bone marrow was collected and transferred into recipient age-matched irradiated naïve mice. Allergic airway disease was induced (8 weeks after adoptive transfer) by sensitization and challenge with ovalbumin. Reconstitution of irradiated naïve mice with bone marrow from mice infected as neonates resulted in the suppression of the hallmark features of allergic airway disease including mucus hyper-secretion and airway hyper-responsiveness, which was associated with decreased IL-13 levels in the lung. In stark contrast, reconstitution with bone marrow from mice infected as infants increased the severity of allergic airway disease by increasing T helper type-2 cell cytokine release (IL-5 and IL-13), mucus hyper-secretion, airway hyper-responsiveness and IL-13 levels in the lung. Reconstitution with bone marrow from infected adult mice had no effects.

Conclusions

These results suggest that an infant chlamydial lung infection results in long lasting alterations in hematopoietic cells that increases the severity of allergic airway disease in later-life.     

Chlamydophila spp. infection in horses with recurrent airway obstruction: similarities to human chronic obstructive disease

Background

Recurrent airway obstruction (RAO) in horses is a naturally occurring dust-induced disease mainly characterized by bronchiolitis which shows histological and pathophysiological similarities to human chronic obstructive pulmonary disease (COPD). In human COPD previous investigations indicated an association with Chlamydophila psittaci infection. The present study was designed (1) to clarify a possible role of this infectious agent in RAO and (2) to investigate the suitability of this equine disorder as a model for human COPD.

Methods

Clinico-pathological parameters of a total of 45 horses (25 horses with clinical signs of RAO and 20 clinically healthy controls) were compared to histological findings in lung tissue samples and infection by Chlamydiaceae using light microscopy, immunohistochemistry, and PCR.

Results

Horses with clinical signs of RAO vs. controls revealed more inflammatory changes in histology (p = 0.01), and a higher detection rate of Chlamydia psittaci antigens in all cells (p < 0.001) and bronchiolar epithelial cells alone (p < 0.001) by immunohistochemistry. The abundance of chlamydial inclusions increased with the severity of disease. PCR was positive in 60% of horses with RAO vs. 45% of the controls (p = 0.316). OmpA sequencing identified Chlamydophila psittaci (n = 9) and Chlamydophila abortus (n = 13) in both groups with no significant differences. Within the group of clinically healthy horses subgroups with no changes (n = 15) and slight inflammation of the small airways (n = 5) were identified. Also in the group of animals with RAO subgroups with slight (n = 16) and severe (n = 9) bronchiolitis could be formed. These four subgroups can be separated in parts by the number of cells positive for Chlamydia psittaci antigens.

Conclusion

Chlamydophila psittaci or abortus were present in the lung of both clinically healthy horses and those with RAO. Immunohistochemistry revealed acute chlamydial infections with inflammation in RAO horses, whereas in clinically healthy animals mostly persistent chlamydial infection and no inflammatory reactions were seen. Stable dust as the known fundamental abiotic factor in RAO is comparable to smoking in human disease. These results show that RAO can be used as a model for human COPD.