Neuroprotective effects of some epigenetic modifying drugs' on Chlamydia pneumoniae-induced neuroinflammation: A novel model.

Chlamydia pneumoniae (Cpn) is a gram-negative intracellular pathogen that causes a variety of pulmonary diseases, and there is growing evidence that it may play a role in Alzheimer's disease (AD) pathogenesis. Cpn can interact functionally with host histones, altering the host's epigenetic regulatory system by introducing bacterial products into the host tissue and inducing a persistent inflammatory response. Because Cpn is difficult to propagate, isolate, and detect, a modified LPS-like neuroinflammation model was established using lyophilized cell free supernatant (CFS) obtained from infected cell cultures, and the effects of CFS were compared to LPS. The neuroprotective effects of Trichostatin A (TSA), givinostat, and RG108, which are effective on epigenetic mechanisms, and the antibiotic rifampin, were studied in this newly introduced model and in the presence of amyloid beta (Aß) 1-42. The neuroprotective effects of the drugs, as well as the effects of CFS and LPS, were evaluated in Aß-induced neurotoxicity using a real-time cell analysis system, total ROS, and apoptotic impact. TSA, RG108, givinostat, and rifampin all demonstrated neuroprotective effects in both this novel model and Aß-induced neurotoxicity. The findings are expected to provide early evidence on neuroprotective actions against Cpn-induced neuroinflammation and Aß-induced neurotoxicity, which could represent a new treatment option for AD, for which there are currently few treatment options.

Intranasal immunization with recombinant chlamydial protease-like activity factor attenuates atherosclerotic pathology following Chlamydia pneumoniae infection in mice.

We have shown previously that intranasal vaccination with recombinant chlamydial protease-like activity factor (rCPAF: antigen) and interleukin-12 (IL-12) as an adjuvant induces robust protection against pathological consequences of female genital tract infection with Chlamydia muridarum, a closely related species and a rodent model for the human pathogen Chlamydia trachomatis. Another related species Chlamydia pneumoniae, a human respiratory pathogen, has been associated with exacerbation of atherosclerotic pathology. CPAF is highly conserved among Chlamydia spp. leading us to hypothesize that immunization with rCPAF with IL-12 will protect against high-fat diet (HFD) and C. pneumoniae-induced acceleration of atherosclerosis. rCPAF ± IL-12 immunization induced robust splenic antigen (Ag)-specific IFN-γ and TNF-α production and significantly elevated serum total anti-CPAF Ab, IgG2c, and IgG1 antibody levels compared to mock or IL-12 alone groups. The addition of IL-12 to rCPAF significantly elevated splenic Ag-specific IFN-γ production and IgG2c/IgG1 anti-CPAF antibody ratio. Following intranasal C. pneumoniae challenge and HFD feeding, rCPAF ± IL-12-immunized mice displayed significantly enhanced splenic IFN-γ, not TNF-α, response on days 6 and 9 after challenge, and significantly reduced lung chlamydial burden on day 9 post-challenge compared to mock- or IL-12-immunized mice. Importantly, rCPAF ± IL-12-immunized mice displayed significantly reduced atherosclerotic pathology in the aortas after C. pneumoniae challenge. Serum cholesterol levels were comparable between the groups suggesting that the observed differences in pathology were due to protective immunity against the infection. Together, these results confirm and extend our previous observations that CPAF is a promising candidate antigen for a multisubunit vaccine regimen to protect against Chlamydia-induced pathologies, including atherosclerosis.

Abortion storm induced by the live C. abortus vaccine 1B strain in a vaccinated sheep flock, mimicking a natural wild-type infection.

Chlamydia abortus is responsible for enzootic abortion (known as ovine enzootic abortion (OEA) and enzootic abortion of ewes (EAE)) in both sheep and goats and has major economic implications for the farming industry worldwide. A virulence-attenuated mutant strain of C. abortus (strain 1B) is currently commercially available as a live attenuated vaccine for immunization of sheep and goats in several European countries. Following an abortion storm in a French flock of 200 ewes that occurred two years after vaccination of 36 replacement ewes with the commercial 1B vaccine strain, the vaginal swabs of 3 vaccinated and 7 unvaccinated aborted ewes and 12 of the 13 dead fetuses were found to be positive for C. abortus by real-time PCR. Genotyping of the samples, using vaccine-specific SNP markers, identified all as positive for the vaccine-type strain. The recent vaccination of this flock with the attenuated commercial vaccine strain, the large number of abortion cases observed in ewes irrespective of vaccination status, the high C. abortus load detected in vaginal swabs or abortion tissues and the identification of specific vaccine-type markers in these samples strongly suggest that the 1B strain has been transmitted from vaccinated to naïve animals, thus mimicking a natural wild-type infection.

Chlamydiaceae and chlamydial infections in sheep or goats.

Chlamydiae induce a range of pathological syndromes in small ruminants. Abortion is the most common clinical expression of the infection that causes important economic losses and presents a risk to human health, particularly in pregnant women. The present paper gives an overview of chlamydial infections in sheep and goats, focusing specifically on abortion and on recent data brought by cellular and genomic approaches regarding genotyping, virulence of strains, epidemiology, diagnosis, pathogenesis and control of the disease.

The complement C3a receptor is critical in defense against Chlamydia psittaci in mouse lung infection and required for antibody and optimal T cell response.

BACKGROUND: The complement system protects against extracellular pathogens and links innate and adaptive immunity. In this study, we investigated the anaphylatoxin C3a receptor (C3aR) in Chlamydia psittaci lung infection and elucidated C3a-dependent adaptive immune mechanisms. METHODS: Survival, body weight, and clinical score were monitored in primary mouse infection and after serum transfer. Bacterial load, histology, cellular distribution, cytokines, antibodies, and lymphocytes were analyzed. RESULTS: C3aR(-/-) mice showed prolonged pneumonia with decreased survival, lower weight, and higher clinical score. Compared to wild-type mice bacterial clearance was impaired, and inflammatory parameters were increased. In lung-draining lymph nodes of C3aR(-/-) mice the total number of B cells, CD4(+) T cells, and Chlamydia-specific IFN-γ(+) (CD4(+) or CD8(+)) cells was reduced upon infection, and the mice were incapable of Chlamydia-specific immunoglobulin M or immunoglobulin G production. Performed before infection, transfer of hyperimmune serum prolonged survival of C3aR(-/-) mice. CONCLUSIONS: C3a and its receptor are critical for defense against C. psittaci in mouse lung infection. In this model, C3a acts via its receptor as immune modulator. Enhancement of specific B and T cell responses upon infection with an intracellular bacterium were identified as hitherto unknown features of C3a/C3aR. These new functions might be of general immunological importance.

Protection of mice against Chlamydophila abortus infection with a bacteriophage-mediated DNA vaccine expressing the major outer membrane protein.

A bacteriophage-delivered DNA vaccine against Chlamydophila abortus was constructed by cloning a eukaryotic cassette containing the ompA gene (which expresses the Major Outer Membrane Protein) into a bacteriophage lambda vector. Four groups, each of 20 BALB/c mice were inoculated separately with the phage vaccine, a conventional DNA vaccine based on the same ompA expression cassette, a live attenuated vaccine (strain 1B) or the empty phage vector. The phage and DNA vaccines and empty phage vector were administered intramuscularly on days 0, 14 and 28; the attenuated vaccine was given once on day 0. Half the animals in each group were challenged on day 42 by intraperitoneal injection of live C. abortus and sacrificed on day 49. Phage-vaccinated mice developed moderate antibody levels against C. abortus and yielded higher levels of IFN-γ and IL-2 compared with the attenuated live vaccine group. Clearance of chlamydiae from spleens was significantly better in the attenuated vaccine group compared with the phage vaccine group, while both groups were significantly superior to the DNA vaccine and control groups (p<0.01). Although levels of protection in the mouse model were lower in phage-vaccinated animals, than in 1B vaccinated animals, phage vaccines offer several other advantages, such as easier handling and safety, potentially cheaper production and no chance of reversion to virulence. Although these are preliminary results in a model system, it is possible that with further optimisation immunization with phage vaccines may provide a novel way to improve protection against C. abortus infection and trials in large animals are currently being initiated.

Treatment and control of chlamydial and rickettsial infections in sheep and goats.

Small ruminants are susceptible to several chlamydial and rickettsial infections. Some of them, such as Ehrlichia ruminantium, have a great impact on the sheep and goat industry while others, such as Coxiella burnetii, are important zoonotic agents. This review focuses on measures of treatment and control for the following organisms: Chlamydophila abortus (formerly Chlamydia psittaci immunotype 1), Coxiella burnetii, Anaplasma ovis, Anaplasma phagocytophilum, and Ehrlichia ruminantium.

Co-administration of the polysaccharide of Lycium barbarum with DNA vaccine of Chlamydophila abortus augments protection.

Lycium barbarum polysaccharides (LBP) can stimulate moderate immune responses therefore could potentially be used as a substitute for oil adjuvants in veterinary vaccines. In the present study, it was shown that the isolated active component of LBP3a, combined with a DNA vaccine encoding the major outer membrane protein (MOMP) of Chlamydophila abortus, induced protection in mice against challenge. Sixty BALB/c mice were randomly assigned to 5 groups. Sub-fractions of polysaccharide LBP3a, at 12.5, 25 and 50 mg/kg concentrations, respectively, were mixed with a pCI-neo::MOMP (pMOMP) vaccine. Mice administrated with pCI-neo + LBP3a were served as a control. All mice were inoculated at day 0, 14, and 28, and challenged on day 44. The effects of LBp3a on serum antibody levels, in vitro lymphocyte proliferation, the activity of interleaukin-2 (IL-2), interferon-γ (IFN-γ), tumor necrosis factor α(TNF-α)and chlamydia clearance were determined. A combination of DNA vaccine and LBP3a induced significantly higher antibody levels in mice, higher T cell proliferation and higher levels of IFN-γ and IL-2. Mice immunized with DNA and LBP3a also showed significantly higher levels of chlamydia clearance in mice spleens and a greater Th1 immune response. The immunoenhancement induced by 25 mg/kg LBP3a is more effective than that induced by a 12.5 and 50 mg/kg. This implies that LBP3a at 25 mg/kg has a high potential to be used as an effective adjuvant with a DNA vaccine against swine Chlamydophila abortus.

Exploiting antigenic diversity for vaccine design: the chlamydia ArtJ paradigm.

We present an interdisciplinary approach that, by incorporating a range of experimental and computational techniques, allows the identification and characterization of functional/immunogenic domains. This approach has been applied to ArtJ, an arginine-binding protein whose orthologs in Chlamydiae trachomatis (CT ArtJ) and pneumoniae (CPn ArtJ) are shown to have different immunogenic properties despite a high sequence similarity (60% identity). We have solved the crystallographic structures of CT ArtJ and CPn ArtJ, which are found to display a type II transporter fold organized in two α-ß domains with the arginine-binding region at their interface. Although ArtJ is considered to belong to the periplasm, we found that both domains contain regions exposed on the bacterial surface. Moreover, we show that recombinant ArtJ binds to epithelial cells in vitro, suggesting a role for ArtJ in host-cell adhesion during Chlamydia infection. Experimental epitope mapping and computational analysis of physicochemical determinants of antibody recognition revealed that immunogenic epitopes reside mainly in the terminal (D1) domain of both CPn and CT ArtJ, whereas the surface properties of the respective binding-prone regions appear sufficiently different to assume divergent immunogenic behavior. Neutralization assays revealed that sera raised against CPn ArtJ D1 partially reduce both CPn and CT infectivity in vitro, suggesting that functional antibodies directed against this domain may potentially impair chlamydial infectivity. These findings suggest that the approach presented here, combining functional and structure-based analyses of evolutionary-related antigens can be a valuable tool for the identification of cross-species immunogenic epitopes for vaccine development.

Evidence of Chlamydophila abortus vaccine strain 1B as a possible cause of ovine enzootic abortion.

Chlamydophila abortus, the agent of ovine enzootic abortion (OEA), is a major cause of lamb mortality worldwide. Disease can be controlled through the use of vaccines based on the 1B temperature-sensitive mutant strain of C. abortus. This study investigated suspected OEA cases across Scotland for the presence of the 1B strain by analysis of recently identified unique point mutations (9). Thirty-five cases were C. abortus-positive and 14 came from vaccinated flocks. Analysis of single nucleotide polymorphisms by PCR-RFLP and sequence analysis revealed the presence of point mutations consistent with the presence of the 1B vaccine strain in 5 of these 14 samples. Quantitative real-time PCR revealed comparable numbers of genome copies of the 1B strain in infected placentas to those present following wild-type infection. This study is the first to demonstrate the presence of the 1B vaccine strain in the placentas of OEA cases and suggests a probable causal role in the disease.

Efficacy of a new inactivated Chlamydophila felis vaccine in experimentally-infected cats.

A new inactivated and adjuvanted Chlamydophila felis vaccine was developed and its efficacy in cats was compared with that of commercially available inactivated and live vaccines. Two commercial vaccines conferred insufficient immunity on inoculated cats, as evaluated by antibody production and a challenge experiment, whereas cats administered the newly generated vaccine produced high-titre antibodies and acquired sufficient immunity. The cats immunised with the new vaccine revealed no or only mild clinical signs, and no chlamydiae were recovered from their tissue samples after exposure to a virulent C felis. However, they shed chlamydiae in their nasal and conjunctival secretions after challenge, as did those immunised with the commercial vaccines and the non-vaccinated controls. The newly developed vaccine caused no adverse reaction in the inoculated cats. These findings suggest that the new vaccine prepared here may be promising for practical use in controlling C felis infection in cats.

Novel Chlamydia pneumoniae vaccine candidates confirmed by Th1-enhanced genetic immunization.

Identification of highly immunogenic antigens is critical for the construction of an efficacious subunit vaccine against Chlamydia pneumoniae infections. A previous project used a genome-wide screen to identify 12 protective C. pneumoniae candidate genes in an A/J mouse lung disease model (Li et al. [14]). Due to insufficient induction of Th1 immunity, these genes elicited only modest protection. Here, we used the Escherichia coli heat-labile enterotoxin as a Th1-enhancing genetic adjuvant, and re-tested these 12 genes, in parallel with six genes identified by other investigators. Vaccine candidate genes cutE and Cpn0420 conferred significant protection by all criteria evaluated (prevention of C. pneumoniae-induced death, reduction of lung disease, elimination of C. pneumoniae). Gene oppA_2 was protective by disease reduction and C. pneumoniae elimination. Four other genes were protective by a single criterion. None of the six genes reported elsewhere protected by reduction of lung disease or elimination of C. pneumoniae, but three protected by increasing survival.

Seroprevalence survey of Chlamydophila abortus infection in breeding goats on commercial farms in the Otavi Veterinary District, northern Namibia.

A total of 1 076 sera from breeding goats were randomly collected from 24 different farms and tested with CHEKIT®-ELISA (IDEXX Laboratories B.V., 1 119 NE Schiphol-Rijk, Nederland) for antibodies against Chlamydophila abortus. The farms were divided into two categories of twelve farms each,based on their previous history of observed abortions over the previous 12 months: those with low (< 5%) levels of abortion and those with high (≥ 5%) levels of abortion. The farmers were also interviewed on their level of awareness about chlamydophilosis, its zoonotic importance and vaccination measures against the disease. The study detected overall seroprevalence levels of 25% for the farms and 8% for the individual animals (at 95% confidence). A total of six out of twentyfour farms (25%) had at least one positive breeding animal. Only five out of the twenty-four (20.8%)farmers interviewed were aware of chlamydophilosis and its zoonotic dangers. None of the 24 farmers interviewed practised any vaccination against chlamydophilosis. There was a significantly higher number of seropositive animals from farms with high levels of abortion, compared to those animals from farms with low levels of abortion (p = 0.0001). This study underscores the need for a higher level of farmer awareness and training on chlamydophilosis and its zoonotic dangers.

Zoonotic potential of Chlamydophila.

The purpose of this article is to present the diseases induced in humans and animals by the different species of Chlamydophila, after providing an overview on the history of these infectious agents and their taxonomy. The route of transmission and the available methods for prevention and control in the different animal species are reviewed.

Effects of dietary lysine supplementation on upper respiratory and ocular disease and detection of infectious organisms in cats within an animal shelter.

OBJECTIVE: To determine within a cat shelter effects of dietary lysine supplementation on nasal and ocular disease and detection of nucleic acids of Chlamydophila felis, feline calicivirus (FCV), and feline herpesvirus (FHV-1). ANIMALS: 261 adult cats. PROCEDURES: Cats were fed a diet containing 1.7% (basal diet; control cats) or 5.7% (supplemented diet; treated cats) lysine for 4 weeks. Plasma concentrations of lysine and arginine were assessed at the beginning (baseline) and end of the study. Three times a week, cats were assigned a clinical score based on evidence of nasal and ocular disease. Conjunctival and oropharyngeal swab specimens were tested for FHV-1, FCV, and C felis nucleic acids once a week. RESULTS: Data were collected from 123, 74, 59, and 47 cats during study weeks 1, 2, 3, and 4, respectively. By study end, plasma lysine concentration in treated cats was greater than that in control cats and had increased from baseline. There was no difference between dietary groups in the proportion of cats developing mild disease. However, more treated cats than control cats developed moderate to severe disease during week 4. During week 2, FHV-1 DNA was detected more commonly in swab specimens from treated versus control cats. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary lysine supplementation in the amount used in our study was not a successful means of controlling infectious upper respiratory disease within a cat shelter. Rather, it led to increases in disease severity and the incidence of detection of FHV-1 DNA in oropharyngeal or conjunctival mucosal swab specimens at certain time points.

Chlamydophila felis infection. ABCD guidelines on prevention and management.

OVERVIEW: Chlamydophila felis is a Gram-negative bacterium and its primary target is the conjunctiva. The bacterium does not survive outside the host. INFECTION: Transmission requires close contact between cats; ocular secretions are probably the most important body fluid for infection. Most cases occur in cats under 1 year of age. Chlamydophila felis is the infectious organism most frequently associated with conjunctivitis. DISEASE SIGNS: Unilateral ocular disease generally progresses to become bilateral. There can be intense conjunctivitis with extreme hyperaemia of the nictitating membrane, blepharospasm and ocular discomfort. Transient fever, inappetence and weight loss may occur shortly after infection, although most cats remain well and continue to eat. DIAGNOSIS: PCR techniques are now preferred for diagnosing C felis infection. Ocular swabs are generally used. In unvaccinated cats, antibody detection can be used to indicate infection. DISEASE MANAGEMENT: Tetracyclines are generally regarded as the antibiotics of choice. Doxycycline has the advantage of requiring only single daily administration and is given at a dose of 10 mg/kg orally. Vaccination should be considered if there is a history of confirmed chlamydial disease in a shelter. Single housing and routine hygiene measures should suffice to avoid cross-infection. Cats maintained together for longer terms should be vaccinated regularly. In breeding catteries where C felis infection is endemic, the first step should be to treat all cats with doxycycline for at least 4 weeks. Once clinical signs have been controlled, the cats should be vaccinated. VACCINATION RECOMMENDATIONS: Vaccination should be considered for cats at risk of exposure to infection. Vaccination generally begins at 8-10 weeks of age, with a second injection 3-4 weeks later. Annual boosters are recommended for cats at continued risk of exposure.

Azithromycin does not prevent six-month myointimal proliferation but attenuates the transient systemic inflammation occurring after coronary stenting.

OBJECTIVES: Stent implantation produces a systemic increase of inflammatory markers that correlates with Chlamydophila pneumoniae infection in atherosclerotic plaque. We performed a clinical intervention study to investigate the effect of antibiotic treatment on 6-month follow-up angiographic minimal luminal diameter after stenting. METHODS: Ninety patients were randomly assigned to oral azithromycin or placebo in a double-blinded and randomized fashion. Medication was initiated 2 weeks before a pre-scheduled stenting procedure and maintained 12 weeks thereafter. Angiographic outcomes were evaluated by a six-month follow-up angiography and laboratorial parameters were accessed by blood sampling 2 weeks before stenting, within the first 24 h after procedure and additional samples after four weeks and 6 months. RESULTS: Minimal luminal diameter (1.76 +/- 0.56 mm Vs. 1.70 +/- 0.86 mm; P = 0.7), restenosis rate, diameter stenosis, late loss, and binary restenosis rates were comparable in placebo and azithromycin group in the 6 months follow-up. Serum levels of C-reactive protein presented a three fold significant increase in the control group one day after stenting but did not change in the azithromycin group (8.5 [3.0;16.4] Vs. 2.9 [1.7;6.6]-median [25;75 percentile] P < 0.01). CONCLUSIONS: Azithromycin does not improve late angiographic outcomes but attenuates the elevation of C-reactive protein levels after stenting, indicating an anti-inflammatory effect.

Induction of a protective immune response against swine Chlamydophila abortus infection in mice following co-vaccination of omp-1 DNA with recombinant MOMP.

Chlamydophila abortus is the causative agent of abortion in pigs and pregnant women. Seroconversion rates were arranged from 11% to 80% in piglets and sows in China. These very high rates illustrate the scale of the problem in China and highlight the urgent need for the development of a C. abortus vaccine. An efficacious anti-chlamydial vaccine should induce not only strong mucosal and systemic T-helper type 1 (Th1) immune response but also give a humoral response that enhances Th1 activation following infection. In order to evaluate an active immune response of a combination of the major outer membrane protein (MOMP) DNA- and protein-based vaccines, 54 BALB/c mice were randomly assigned to six groups and inoculated intramuscularly with: (i) 100 microg pcDNA::MOMP, (ii) 10 microg r-MOMP, (iii) primed with 100 microg pcDNA::MOMP and boosted with 10 microg r-MOMP, (iv) primed-boosted with a combination of pcDNA::MOMP and r-MOMP simultaneously, (v) live-attenuated 1B vaccine, (vi) 100 microg pcDNA3.1 vector. All animals were vaccinated two times at 14 days intervals. Results showed that mice given DNA and r-MOMP induced higher antibody levels, higher T cells proliferation and an elevated level of chlamydial clearance in spleen, which was equivalent to the clearance of 1B vaccine. Mice administrated the DNA-primed/MOMP-boosted approach elicited moderate antibody levels, less T-lymphocyte proliferation and lower chlamydial clearance as compared with 1B vaccine. Co-immunization with DNA- and r-MOMP vaccine may provide novel ways for active immunization strategy against swine C. abortus.