Chlamydia pneumoniae in atherosclerotic middle cerebral artery

Background and Purpose—Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke. Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. Methods—Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. Results—Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. Conclusions—The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases

Az atherosclerosis és Chlamydia pneumoniae fertőzések összefüggésének genetikai háttere = The genetic background of the interactions between atherosclerosis and Chlamydia pneumoniae infections

Atherosclerotikus plakkokban gyakran a Chlamydophila pneumoniae (C. pneumoniae) DNS és human cytomegalovirus (HCMV) DNS közös jelenléte mutatható ki. A kettősen fertőzött monocytákban az atherosclerosisban szerepet játszó gének expressziója jön létre. A HCMV-vel (Oslo törzs) fertőzött dendritikus sejtekben (DC) a virus nem szaporodik, de a HCMV-vel fertőzött fibroblast sejtek által termelt faktorok a DC érését indítják el. A DC fertőzése C. pneumoniae-val elindítja a DC érését, de a fertőző baktériumok szaporodasát nem. Bizonyos chlamydiális transzkriptok kifejezőséde megtörténik, de a baktérium osztódásásban szerepet jatszó ftsK gén mRNA expressziója nem. Akut nem-cardioembóliás eredetű stroke betegek és kontroll egyének vérének vizsgálata szerint a CD14 és IL-8 promoter polimorfizmusok nem jatszanak szerepet a stroke kialakulásában. A stroke betegekben szignifikánsan magasabb a HCMV-IgG és HSV-1 IgA ellenanyag szint. Percutan transluminalis angioplasztikai beavatkozás után a C. pneumoniae DNS és HCMV DNS kimutathatósága fokozott, a hisztamin, CRP, és IL-6 szintek emelkedettek. Egér modellen az egyszeri vagy ismételt C. pneumoniae fertőzés bakteriális perzisztenciát eredményez. | Chlamydophila pneumoniae (C. pneumoniae) is often present in combination with human cytomegalovirus (HCMV) in atherosclerotic carotid lesions. The doubly-infected monocytes are potent expressors of proatherosclerotic genes. The HCMV (strain Oslo) does not replicate in infected dendritic cells (DC), however HCMV conditioning medium harvested from human fibroblast cells induce the expression of maturation markers on the DC. Full replication of C. pneumoniae in DC is not observed, but C. pneumoniae infection induce the maturation and functional activation of DC. Some chlamydial genes are expressed, but the expression of the division-related ftsK gen is limited. By analyzing blood samples of patients with acute noncardioembolic ischemic stroke and control individuals, the IL-8 or CD14 promoter polymorphisms are not related with the development of the disease. Serum levels of HCMV-IgG and HSV-1 IgA are higher in the patients than in the controls. Reactivation of C. pneumoniae and HCMV and increased levels of histamine, CRP and IL-6 followoing percutan transluminal angioplasty are observed. A single or repeated inoculation of mice with C. pneumoniae result in bacterial persistence in a few mice

Association of Chlamydia pneumoniae with coronary artery disease and its progression is dependent on the modifying effect of mannose-binding lectin

Background— The possible association between coronary artery disease (CAD) and Chlamydia pneumoniae (C pneumoniae) infection is controversial. On the basis of the recent suggestion that mannose-binding lectin (MBL) variant alleles are related to an increased risk of severe atherosclerosis, and on the in vitro interaction of MBL with C pneumoniae, we asked whether MBL might contribute to CAD in conjunction with C pneumoniae. Methods and Results— Antibodies to C pneumoniae were measured by immunofluorescence and MBL alleles were determined by polymerase chain reaction technique in samples from 210 patients with CAD and 257 healthy subjects from Hungary collected between 1995 and 1996. A higher percentage of patients with CAD were anti-C pneumoniae positive as compared with the control group (P=0.058). However, at logistic regression analysis adjusted to age, sex, and serum lipid levels, this difference was confined only to subjects carrying MBL variant alleles (P=0.035, odds ratio 2.63, [95% CI: 1.07 to 6.45]). In contrast, no significant difference was seen in those homozygous for the normal MBL allele (P=0.412). During a 65±5.8-month follow-up period, major outcomes (new myocardial infarction, and/or bypass operation or cardiovascular death) occurred in 11 C pneumoniae positive and 3 C pneumoniae negative patients. In the C pneumoniae positive group, the odds ratio of development of outcomes was 3.27 (95% CI: 1.10 to 9.71, P=0.033) in the carriers of the MBL variant alleles compared with the homozygous carriers of the normal MBL allele. Conclusions— These results indicate that infection with C pneumoniae leads mainly to the development and progression of severe CAD in patients with variation in the MBL gene

Independent and joint effects of antibodies to human heat-shock protein 60 and Chlamydia pneumoniae infection in the development of coronary atherosclerosis

Background—Studies have suggested that the prevalence of antibodies against heat-shock proteins (HSPs), Chlamydia pneumoniae (Cpn), and cytomegalovirus (CMV) is associated with coronary artery disease (CAD), but the independent or joint effects of human (h) HSP60 antibodies and these pathogens in patients have not been fully elucidated. Methods and Results—A total of 405 subjects (276 patients with CAD and 129 control individuals) were tested for serum antibodies to hHSP60, Cpn, and CMV immediate-early-1 (IE1) antigens. Patients were also assessed for serum cholesterol, triglyceride levels, and smoking habit. Significantly elevated levels of antibodies to hHSP60 and Cpn but not to CMV-IE1 antigens were documented in CAD patients. Multiple logistic regression analysis and subanalyses of selected subjects showed that these associations were independent of age, sex, smoking, and serum lipid levels. Antibodies to hHSP60 and Cpn did not correlate quantitatively; however, the relative risk of disease development was substantially increased in subjects with high antibody levels to both hHSP60 and Cpn, reaching an odds ratio of 82.0 (95% CI 10.6 to 625.0). Conclusions—High levels of antibodies to hHSP60 and Cpn are independent risk factors for coronary atherosclerosis, but their simultaneous presence substantially increases the risk for disease development

Immunization of Chlamydia pneumoniae (Cpn)-infected Apob(tm2Sgy)Ldlr(tm1Her)/J mice with a combined peptide of Cpn significantly reduces atherosclerotic lesion development

OBJECTIVE: To investigate the antigenic effect of a peptide containing two epitopes of Chlamydia pneumoniae (Cpn) on atherosclerotic lesion formation in mice infected with Cpn. MATERIALS AND METHODS: Six-week-old Apob(tm2Sgy)Ldlr(tm1Her)/J mice were immunized using a repetitive immunization multiple-sites strategy with KLH-conjugated peptides derived from the major outer membrane protein and the putative outer membrane protein 5 of Cpn. Mice were fed a high-fat diet and infected with Cpn twice during the 10-week diet period. Lesions were evaluated histologically; local and systemic immune responses were analyzed by immunohistochemistry of aorta samples and cytokine measurements in plasma samples and splenocyte supernatants. RESULTS: Mice immunized with the combined Cpn peptide showed a greater reduction in lesion size compared to mice immunized with either epitope alone [54.7% vs 39.8% or 41.72%] and was also associated with a significant decrease in lesion area in descending aortas compared with those in controls (88.9% for combined Cpn peptide, 81.9% for MOMP peptide and 75.7% for Omp5, respectively). This effect was associated with a shift in the cellular composition of plaques towards decreased inflammatory cell and increased regulatory T-cell content. Additionally, the effect was also connected with decreased secretion of proinflammatory cytokines and increased production of anti-inflammatory cytokines demonstrated in plasma and in supernatant on stimulated spleen cells. CONCLUSIONS: Atherosclerotic lesion formation may be promoted by Cpn infection in the presence of a high-fat diet, and reduced by immunization with the combined Cpn peptide. The combined peptide has more potential than either epitope alone in reducing atherosclerotic lesion development through Treg expansion

Human cytomegalovirus latency is associated with the state of differentiation of the host cells: an in vitro model in teratocarcinoma cells.

The human cytomegalovirus (HCMV) major immediate-early (MIE) gene is not transcribed in undifferentiated NTera-2 embryonal carcinoma cells, but is transcribed in their differentiated derivatives, offering a model with which to study the developmental regulation of the activity of a viral gene during the differentiation of these cells. Themolecularmechanisms involved in the blockade of theMIE gene expression in undifferentiated NTera2 cells include covalent closure of the circular conformation of the viral genome, silencing of the viralMIE promoter by histone deacetylation, and increases in the expression of negatively regulating transcription factors responsible for the recruitment of the histone deacytylases around the viralMIE promoter (MIEP), resulting in repression of the MIEP in undifferentiated cells. The treatment of NTera2 cells with retinoic acid induces the differentiation of these cells. In HCMV-infected differentiated NTera2 cells, the MIEP becomes associated with hyperacetylated histones, which results in an open structure of chromatin, enhancing the access of DNA- binding factors which positively regulate MIE gene expression and viral replication. This model system contributes to an understanding of HCMV latency and reactivation in vivo in the cells of the myeloid lineage

Preclinical evaluation of an ALVAC (canarypox)-human cytomegalovirus glycoprotein B vaccine candidate

Successful vaccination against the human cytomegalovirus (HCMV) requires induction. of both neutralizing antibody and cytotoxic T lymphocyte (CTL) responses. The HCMV glycoprotein B (gB, UL55) would be one of the most important immunogens to induce neutralizing antibodies. We tested the immunogenicity of art ALVAC (canarypox)-HCPAV-gB (ALVAC-gB) recombinant in mice and guinea pigs in order to provide preclinical data for a phase I clinical trial of a HCMV vaccine candidate, AL VAC is an attenuated vaccine strain of canarypox virus which replicates productively in avian species but abortively in mammalian cells, The ALVAC-gB recombinant inoculated subcutaneously in mice and intramuscularly in guinea pigs induced HCMV-specific neutralizing antibodies and gB-specific CTL responses. Ultraviolet irradiation of the ALVAC-gB recombinant before immunization diminished CTL responses, indicating that intracellular expression and processing of gB-protein were necessary for CTL induction. Prior immunity to vaccinia virus did Plot decrease immunogenicity of the ALVAC-gB recombinant in mice. Thus, despite its host range restriction, ALVAC-gB is potentially capable of inducing both humoral and cell-mediated immune responses to HCMV in both vaccinia-immune and non-immune individuals