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Chlamydia pneumoniaeis a common respiratory pathogen that is associated with an increased risk of cardiovascular disease. However, the mechanisms by whichC. pneumoniaecontributes to cardiovascular disease have not been determined yet.C. pneumoniaeinfection may accelerate the death of cells within atherosclerotic lesions and contribute to the formation of unstable lesions. To test this hypothesis, the impact ofC. pneumoniaeinfection on the death of lipid-loaded mouse macrophages was investigated. It was observed that RAW 264.7 cells are highly susceptible to the toxic effects of oxidized low-density lipoprotein (LDL) and exhibit markers of cell death within 24 h of treatment with as little as 5 μg/ml oxidized LDL. Subsequent infection with either liveC. pneumoniaeor heat-killed or UV-inactivatedC. pneumoniaeat a low multiplicity of infection for 24 to 72 h stimulated both additional binding of annexin V and the uptake of propidium iodide. Thus,C. pneumoniaeaugments the effects of oxidized LDL on cell death independent of a sustained infection. However, unlike oxidized LDL,C. pneumoniaeinfection does not activate caspase 3 or induce formation of the mitochondrial transition pore or the fragmentation of DNA, all of which are classical markers of apoptosis. Furthermore, primary bone marrow macrophages isolated from mice deficient in Toll-like receptor 2 (TLR-2) but not TLR-4 are resistant toC. pneumoniae-induced death. These data suggest thatC. pneumoniaekills cells by a caspase-independent pathway and that the process is potentially mediated by activation of TLR-2.

The role of tumor necrosis factor alpha (TNF-α) inChlamydia pneumoniaeatherogenesis was evaluated in TNF-α p55 receptor-deficient C57BL/6J mice fed a high-fat/high-cholesterol diet. No acceleration of atherosclerotic lesion development was observed in infected mice compared to uninfected mice, indicating that TNF-α plays a role in the acceleration of atherosclerosis byC. pneumoniae.

Results of performance testing of three types of commercial self-contained breathing apparatus (SCBA) facepieces are described. A series of tests were performed to determine sarin (GB) and distilled sulfur mustard (HD) vapor breakthrough of SCBA facepieces using manikin head form and simulated breathing.

Results of performance testing of the CB4O CNR Air Purifying Full Face Respirator are described. Three series of tests were performed: (1) breakthrough time determinations of cartridges/canisters against sarin (GB), (2) GB vapor breakthrough determination of entire system using manikin headform and simulated breathing, and (3) corn-oil protection factor determinations of system using human subjects. Results indicate that canisters provide adequate resistance to GB breakthrough against high-concentration challenges, and that corn oil aerosol and high-concentration GB vapor penetration into the breathing zone of the respirator occur at acceptable levels.

Two escape hood designs (Draeger DefendAir and the Fume Free Quick Mask 2000) were tested to assess their capability to protect in a chemical warfare (CW) agent environment. Sarin and mustard vapor tests were performed on both types of hoods, and there were no breakthroughs during the 65-min tests. The hoods were also tested to assess their ability to protect the wearer from an aerosolized threat. Human test subjects donned the hoods and entered a corn oil aerosol chamber. The Draeger DefendAir achieved a 95.8% pass rate at a PF of 2,000, and the Fume Free Quick Mask 2000 achieved a 100% pass rate at a PF of 2,000.

Objective: Chlamydia pneumoniae infection has been associated with atherosclerosis, although the mechanisms by which C . pneumoniae contribute to atherogenesis remain unclear. Altered production of nitric oxide, a known bactericidal and anti-inflammatory agent, represents one possible mechanistic link. To examine this issue, a diet-induced, hyperlipidemic mouse model of early atherosclerosis was used. Methods: A series of intranasal inoculations of C . pneumoniae strain AR-39 were administered to mice lacking endothelial or inducible nitric oxide synthase and to normal controls. After 18 weeks on an atherogenic diet, atherosclerotic lesion area in the aortic sinus was measured using computer-assisted morphometry. Results: In the absence of C . pneumoniae infection, diet-fed eNOS−/− mice developed enlarged fatty streak lesions of borderline significance in comparison to uninfected, wild-type mice, while the lesion area in uninfected, diet-fed iNOS−/− mice did not differ significantly from lesion area in wild-type animals. In contrast, lesion area in infected eNOS−/− mice increased slightly, but not significantly in comparison to uninfected eNOS−/− mice. Lesion area in the infected iNOS−/− mice was significantly enlarged when compared to both uninfected iNOS−/− mice as well as to infected wild-type mice. Conclusions: These data suggest that production of nitric oxide by eNOS protects against development of fatty streak lesions in uninfected hyperlipidemic mice, but does not offer additional protection in infected hyperlipidemic mice, while iNOS may play a protective role, thus limiting chlamydial exacerbation of fatty streak lesions.

Objective Inflammation contributes to atherosclerotic plaque initiation and progression. Recent studies suggest that anti-inflammatory drugs such as cyclooxygenase-2 (Cox-2) inhibitors have anti-atherogenic effects. The current study was designed to investigate whether administration of a Cox-2 inhibitor to older apolipoprotein E deficient (apo E-/-) mice with established lesions alters the composition and increases the stability of the lesions. Methods and results The Cox-2 inhibitor Celecoxib was administered in chow to 26-week-old, male, apo E-/- mice exhibiting advanced, unstable atherosclerotic lesions within the innominate/brachiocephalic artery. Mice administered Celecoxib had no significant changes in serum cholesterol or the average cross sectional area of atherosclerotic lesion in the innominate artery after 15 weeks of treatment in comparison to non-treated control mice. Histological analyses of sections of the innominate artery demonstrated no significant changes in the frequency of markers of advanced and unstable atherosclerotic plaques, including intra-plaque hemorrhage, vascular calcification, thinning of the fibrous cap, size of the necrotic core and macrophage content. There were also no significant differences in the content of Cox-2 within the lesions. Quantitative real time polymerase chain reaction with mRNA isolated from the aorta of each mouse revealed no significant changes in the expression of tissue factor and inducible nitric oxide synthase. However, mRNA levels for MCP-1 were increased fivefold following 15 weeks of treatment with Celecoxib in comparison to non-treated control mice. Conclusions These data suggest that Celecoxib has no effect on the composition of advanced atherosclerotic lesions in older apo E-/- mice.

Results of performance testing of commercial air-purifying negative pressure respirators (NPR) are described. Three series of tests were performed: (1) breakthrough time determinations of cartridges/canisters against Sarin (GB), (2) GB vapor breakthrough determination of entire NPR systems using mankind headform and simulated breathing, and (3) corn-oil protection factor determinations of NPR systems using human subjects. Results indicate that cartridges provide adequate resistance to GB breakthrough against high-concentration challenges. However, corn oil aerosol and high-concentration GB vapor penetration into the breathing zone of the NPR occurs at unacceptable levels.

Results of performance testing of commercial powered air purifying respirator (PAPR) systems and cartridges are described. Three series of tests were performed: (1) breakthrough time determinations of cartridges against Sarin (GB); (2) GB vapor penetration determination of entire PAPR systems using manikin headform and simulated breathing; and (3) corn-oil protection factor determinations of PAPR systems using human subjects. Results indicate that cartridges provide complete penetration resistance against 200 mg/m(3) GB challenge concentrations for 60 min, but unacceptably high levels of GB vapor and corn oil aerosol may penetrate into the breathing zone of the PAPRs.

Chlamydia pneumoniae is a human respiratory pathogen that causes acute respiratory disease. Multiple studies have associated C. pneumoniae with cardiovascular disease including seroepidemiologic studies, direct detection of the organism within the lesion, and isolation of the organism from atheromatous tissue. The most critical question to be answered by researchers in the field is whether C. pneumoniae plays a role in atherogenesis. This review summarizes in vitro studies, results in animal models of C. pneumoniae infection and atherogenesis, and human intervention studies that provide some support of a mechanistic role.

Ten different feature vectors are tested in a gesture recognition task which utilizes 3D data gathered in real-time from stereo video cameras, and HMMs for learning and recognition of gestures. Results indicate velocity features are superior to positional features, and partial rotational invariance is sufficient for good performance.

A new method for representing and recognizing human body movements is presented. The basic idea is to identify sets of constraints that are diagnostic of a movement: expressed using body-centered coordinates such as joint angles and in force only during a particular movement. Assuming the availability of Cartesian tracking data, we develop techniques for a representation of movements defined by space curves in subspaces of a "phase space." The phase space has axes of joint angles and torso location and attitude, and the axes of the subspaces are subsets of the axes of the phase space. Using this representation we develop a system for learning new movements from ground truth data by searching for constraints. We then use the learned representation for recognizing movements in unsegmented data. We train and test the system on nine fundamental steps from classical ballet performed by two dancers; the system accurately recognizes the movements in the unsegmented stream of motion. >

Chlamydia pneumoniae has been shown to accelerate atherosclerotic lesion development in hyperlipidemic animals. This study showed that C. pneumoniae did not accelerate lesion development in mice if a high-fat/high-cholesterol diet was started after infection, indicating that C. pneumoniae is a co-risk factor with hyperlipidemia for cardiovascular disease.

Chlamydia pneumoniae can infect arterial cells. It has been shown that coculture of human monocytes (U937) and endothelial cells promotes infection of C. pneumoniae in endothelial cells and that the enhancement was mediated by a soluble factor (insulin-like growth factor 2) secreted by monocytes. In this study, it is shown that coculture of monocytes with C. pneumoniae enhances infection of C. pneumoniae in arterial smooth-muscle cells 5.3-fold at a monocyte-to-smooth-muscle cell ratio of 5. However, unlike endothelial cells, no enhancement was observed if monocytes were placed in cell culture inserts or if conditioned medium from monocyte cultures was used, which suggests that cell-to-cell contact is critical. The addition of mannose 6-phosphate or octyl glucoside, a nonionic detergent containing a sugar group, to cocultures inhibited the enhancement. These findings suggest that the monocyte-smooth-muscle cell interaction may be mediated by mannose 6-phosphate receptors present on monocytes.

To the Editor: In contrast to several previously published studies,1–3⇓⇓ the one by Caligiuri et al4 failed to observe an accelerating effect of Chlamydia pneumoniae infection on atherosclerotic lesion development in apolipoprotein E–deficient mice. There are several critical differences in experimental design that likely account for these contrasting observations. In their initial studies, Caligiuri et al4 administered a single, nonpurified, low titer dose of C pneumoniae (1×106 ifu/mouse). This method is in contrast to the other studies where multiple inoculations of higher titers of purified C pneumoniae (5×106 to 3×107 ifu/mouse) were administered at intervals of 1 or 2 weeks. We have previously demonstrated that a single inoculation in animals at 8 weeks of age does not produce a sustained infection in the aorta, whereas multiple inoculations lead …

It has been shown that N-linked high mannose type oligosaccharides competitively inhibits attachment to and infectivity of chlamydiae in HeLa cells. To further study whether mannose moieties are involved in the infectivity of chlamydiae, the susceptibility of mannose-receptor negative J774A and positive J774E mouse macrophages to Chlamydia trachomatis, Chlamydia psittaci and Chlamydia pneumoniae was evaluated. C. trachomatis infected mannose-receptor positive cells better than mannose-receptor negative cells. C. psittaci infected both mannose-receptor negative and positive cells equally well, while C. pneumoniae infected mannose-receptor negative cells better than mannose-receptor positive cells. Further studies using this system may provide insight into the role of mannose-receptor in attachment, entry and survival of chlamydiae in macrophages.

Considerable evidence of an association between Chlamydia pneumoniae infections and cardiovascular disease has emerged. Animal models using genetically altered mice and hypercholesterolemic rabbits have shown a pathogenic role of C. pneumoniae in accelerating atherosclerotic plaque development. In the present study, we evaluated the effect of chronic C. pneumoniae infection on atherosclerosis in C57BL/6J mice, fed either a regular chow diet or a high fat, high cholesterol diet. Infected animals on an atherogenic diet developed significantly larger lesion areas compared with control mice at 18 weeks (2.5-fold increase; 4177+/-777 vs. 1650+/-808 microm(2); P0.05) and 24 weeks of age (3.3-fold increase; 14139+/-4147 vs. 4298+/-869 microm(2); P0.02). This study shows that chronic C. pneumoniae infection accelerates atherosclerotic lesion development in diet induced hypercholesterolemic mice, indicating that C. pneumoniae is a co-risk factor of hyperlipidemia in atherogenesis.

Results of performance testing of the 3M Model BE10 powered air-purifying respirator (PAPR) are described. Three series of tests were performed: (1) breakthrough time determinations of PAPR Cartridge Model AP3 against sarin (GB); (2) GB vapor penetration determination of entire PAPR systems using manikin headform and simulated breathing, and (3) corn-oil protection factor determinations of PAPR systems using human subjects. Results indicate that cartridges provide adequate resistance to GB penetration against high-concentration challenges, but that corn oil aerosol and high-concentration GB vapor penetration into the breathing zone of the PAPR occurs at high levels, possibly through the hood-type head enclosure and/or the exhalation valve.

We have previously demonstrated that Chlamydia pneumoniae accelerates plaque formation in apolipoprotein E-deficient (ApoE −/− ) mice following intranasal inoculations. In this study, we evaluated the effect of respiratory tract infection with Chlamydia trachomatis on the progression of atherosclerosis in ApoE −/− mice. The study showed that in contrast to infection with Chlamydia pneumoniae , infection of the lung and aorta with C. trachomatis was mild and transient and did not significantly accelerate plaque development.

In literature in which detection of Chlamydia pneumoniae in the artery is described, the methods used were immunocytochemistry (ICC), polymerase chain reaction (PCR), electron microscopy, and isolation. These studies demonstrated the presence of the organism in atheromatous lesions. The organism was detected frequently by ICC and PCR in atheromatous tissues (approximately 50% of subjects) but rarely in normal arteries (approximately 1% of subjects). There has been poor correlation between detection and serology. Detection studies have been used to assess the etiologic role of C. pneumoniae in atherosclerosis and to determine whether C. pneumoniae infection contributes to acute cardiovascular events. Although these studies produced suggestive evidence of an etiologic role, the use of observational studies to obtain a definitive answer is difficult. Therefore, investigators are increasingly concentrating their efforts on studies that use animal models, in vitro cultured arterial cells, and therapeutic trials in humans to determine the pathogenic role of the organism in atherosclerosis.

To determine the mechanism(s) by which Chlamydia pneumoniae homes to and establishes persistent infection in atheromatous lesions, the effect of the interaction of monocytes/macrophages (U937 cells) with human umbilical vein endothelial cells (HUVECs) and transformed human arterial endothelial cells (HMEC-1s) on the susceptibility of endothelial cells to infection with C. pneumoniae was investigated. Infection was enhanced 4.7-fold (HUVECs) and 4.4-fold (HMEC-1s) after coculture at monocyte-to-endothelial cell ratios of 5 and 2.5, respectively. U937 cells also directly transmitted infection to the endothelial cells, and addition of U937 cell-conditioned media dose-dependently enhanced the infectivity 2.0- to 2.5-fold. The stimulation of infectivity was specific to endothelial cells, because coculturing of monocytes with epithelial cells did not enhance the susceptibility of epithelial cells to infection. The susceptibility of endothelial cells to infection with C. trachomatis and C. psittaci was not enhanced by the monocyte-derived factor(s).

Accumulating evidence supports an association between Chlamydia pneumoniae infection and atherosclerosis. To determine whether there is a causal relationship, the effects of chronic infection with C. pneumoniae on the development of atherosclerosis in apolipoprotein E (apoE)-deficient mice were evaluated. Eight-week-old male apoE-deficient mice were inoculated intranasally with C. pneumoniae three times, at 8, 9, and 10 weeks of age. The combined area of atherosclerotic lesions in the lesser curvature of the aortic arch was measured en face by computer-assisted morphometry. The lesion area was 2.4-fold greater (P = .05) at 16 weeks of age and 1.6-fold greater (P = .05) at 20 weeks of age in infected mice than in control mice. There were no differences in total plasma cholesterol levels between groups. This study demonstrates that C. pneumoniae infection accelerates the progression of atherosclerosis in the aortic arch of apoE-deficient mice.

In this paper we describe the computational and architectural requirements for systems which support real-time multimodal interaction with an embodied conversational character. We argue that the three primary design drivers are real-time multithreaded entrainment, processing of both interactional and propositional information, and an approach based on a functional understanding of human face-to-face conversation. We then present an architecture which meets these requirements and an initial conversational character that we have developed who is capable of increasingly sophisticated multimodal input and output in a limited application domain.

In this paper, we argue for embodied corrversational characters as the logical extension of the metaphor of human - computer interaction as a conversation. We argue that the only way to fully model the richness of human I&+ to-face communication is to rely on conversational analysis that describes sets of conversational behaviors as fi~lfilling conversational functions, both interactional and propositional. We demonstrate how to implement this approach in Rea, an embodied conversational agent that is capable of both multimodal input understanding and output generation in a limited application domain. Rea supports both social and task-oriented dialogue. We discuss issues that need to be addressed in creating embodied conversational agents, and describe the architecture of the Rea interface.

There is mounting evidence to suggest that Chlamydia pneumoniae might play a role in atherosclerosis. Serological studies and detection of the microorganism in atheromatous lesions were the first indications of an association between C. pneumoniae and the disease. Studies suggest that anti-chlamydial chemotherapy has a favorable effect on cardiovascular disease in humans. Moreover, infection of animals with C. pneumoniae induces inflammatory changes in the aorta that are suggestive of atherosclerosis and accelerates the progression of existing atherosclerotic lesions. If the pathogenic role of C. pneumoniae in atherosclerosis is defined more conclusively by future studies, the development of preventive or therapeutic measures against infection might provide an effective strategy to reduce the risk of atherosclerosis.

Chlamydia pneumoniae has been postulated to cause systemic disease by infection of monocytes/macrophages and spread via the blood or lymphatics. To investigate how C. pneumoniae disseminates, the ability of the organism to infect murine macrophages in vivo and whether infection can be transferred via macrophages were determined. C. pneumoniae was detected by direct plating, isolation, and polymerase chain reaction in alveolar macrophages from intranasally inoculated mice and peritoneal macrophages from intraperitoneally inoculated mice. C. pneumoniae were also detected in peripheral blood mononuclear cells, but not plasma, of intranasally and intraperitoneally inoculated mice. When alveolar or peritoneal macrophages were adoptively transferred by intraperitoneal injection from infected to uninfected mice, C. pneumoniae DNA was detected by polymerase chain reaction in lung, thymus, spleen, and/or abdominal lymph nodes. These results demonstrate the ability of C. pneumoniae to infect macrophages in vivo and to disseminate systemically via infected macrophages by hematogenous and lymphatic routes.

Chlamydia pneumoniae has been associated with atherosclerotic cardiovascular disease by both seroepidemiologic studies and direct detection of the organism in atherosclerotic plaque by electron microscopy (EM), immunocytochemistry (ICC), and polymerase chain reaction (PCR). Despite the frequent detection of the organism in atheromatous cardiovascular specimens by these methods, only 1 cardiovascular isolate of C. pneumoniae, obtained from a coronary artery, has been previously reported. This study reports the isolation of C. pneumoniae from a prospectively obtained carotid endarterectomy specimen. The organism appears to be identical to other C. pneumoniae isolates by EM morphology, reactivity to species-specific monoclonal antibodies, and Southern hybridization analysis of chromosomal digests using C. pneumoniae-specific DNA probes. C. pneumoniae was detected by PCR or ICC (or both) in 11 (69%) of 16 other endarterectomy specimens tested by both of these methods. These results provide further evidence for an association of C. pneumoniae and atherosclerosis by confirming the presence of viable bacteria within atherosclerotic plaque.

Chlamydia pneumoniae have been demonstrated in atherosclerotic lesions but not in normal arteries. An animal model of both C. pneumoniae and atherosclerosis is needed to investigate the role of the organism in atherosclerosis. Apolipoprotein (apo) E-deficient transgenic mice, which spontaneously develop atherosclerosis, and C57BL/6J mice, which only develop atherosclerosis on an atherogenic diet, were evaluated. Following single and multiple intranasal inoculations of apoE-deficient transgenic mice, C. pneumoniae were detected in lung, aorta, and spleen for 20 weeks after inoculation in 25%-100% of mice. In the aorta, C. pneumoniae were detected within the atherosclerotic lesion. In C57BL/6J mice on a nonatherogenic diet, C. pneumoniae were detected in the aorta only 2 weeks after a single intranasal inoculation in 8% of mice. The persistence of C. pneumoniae in atheromas suggests a tropism of C. pneumoniae to the lesion. These mouse models should be useful for studying the pathogenic role of C. pneumoniae in atherosclerosis.

The 1995 program in Geophysical Fluid Dynamics addressed 'Rotating Convection,' with particular emphasis on high Rayleigh number convection and on convection in the ocean.

Background Chlamydia pneumoniae has been demonstrated in atherosclerotic lesions of coronary arteries and aorta. A seroepidemiological study found C pneumoniae –specific antibody more frequently in persons with significant carotid artery wall thickening than in matched control subjects. Methods and Results Fresh-frozen or formalin-fixed tissue obtained at carotid endarterectomy was examined by immunocytochemistry (ICC) and the polymerase chain reaction (PCR) for the presence of C pneumoniae. Five of five fresh-frozen and formalin-fixed carotid endarterectomy specimens were positive for C pneumoniae by ICC (three of five by PCR). A total of 56 archival formalin-fixed, paraffin-embedded carotid endarterectomy tissues from three hospitals were examined by ICC. Thirty-two were positive. Thirteen normal carotid artery tissue sections from six patients were negative for C pneumoniae . Conclusions C pneumoniae organisms are frequently found in the advanced carotid atherosclerotic lesions of persons undergoing endarterectomy. Although these findings do not establish causality for C pneumoniae in carotid artery atherosclerosis, they should stimulate investigation of a possible causal or pathogenic role for the organism in the disease.

Chlamydia pneumoniae (TWAR) is a recently recognized third species of the genus Chlamydia that causes acute respiratory disease. It is distinct from the other two chlamydial species that infect humans, C. trachomatis and C. psittaci, in elementary body morphology and shares less than 10% of the DNA homology with those species. The organism has a global distribution, with infection most common among children between the ages of 5 and 14 years. In children, TWAR infection is usually mild or asymptomatic, but it may be more severe in adults. Pneumonia and bronchitis are the most common clinical manifestations of infection, and TWAR is responsible for approximately 10% of cases of pneumonia and 5% of cases of bronchitis in the United States. The microimmunofluorescence serologic assay is specific for TWAR and can distinguish between recent and past infections. The organism can be isolated in cell culture; however, PCR techniques have recently facilitated its detection in tissues and clinical specimens.

An association of Chlamydia pneumoniae with atherosclerosis of coronary and carotid arteries and aorta has been found by seroepidemiology and by demonstration of the organism in atheromata. Age-matched control tissue from persons without atherosclerosis was usually not available. We studied autopsy tissue from young persons, many with no atherosclerosis, to determine whether C. pneumoniae is present in atheroma in young persons with early atherosclerosis and to compare the findings in age- and sex-matched persons without atherosclerosis. A left anterior descending coronary artery sample, formalin-fixed, from 49 subjects, 15-34 years of age, from the multicenter study called Pathobiological Determinants of Atherosclerosis in Youth (PDAY), was examined by immunocytochemistry and the polymerase chain reaction (PCR) for the presence of C. pneumoniae and by PCR for cytomegalovirus. A hematoxylin/eosin-stained section was used to determine disease present in the studied sample. Seven of the artery samples were found to have atheromatous plaque, 11 had intimal thickening, and 31 had no lesions. Eight of the samples were positive for C. pneumoniae by immunocytochemistry (n = 7) and/or PCR (n = 3). Six of the 7 (86%) atheroma, 2 of the 11 (18%) with intimal thickening, and none of the 31 normal-appearing coronary samples were positive. Four were positive by PCR for cytomegalovirus, 2 from diseased arteries and 2 from normal arteries. Examination of the adjacent left coronary artery sample with a fat stain found abnormalities in 25 of the patients, but 19 still showed no evidence of atherosclerosis as a result of either examination. Thus, C. pneumoniae is found in coronary lesions in young adults with atherosclerosis but is not found in normal-appearing coronary arteries of both persons with and without other evidence of atherosclerosis.

We studied the effects of two antibiotic regimens on the course of Chlamydia pneumoniae infection in the lungs of Swiss Webster mice. After intranasal challenge with isolates AR-388 (1.3 x 10(7) inclusion-forming units per mouse) and AR-39 (1.5 x 10(6) inclusion-forming units per mouse), groups of animals were treated with either doxycycline (10 mg/kg of body weight once a day for 3 days), azithromycin (10 mg/kg [single dose]), or saline. Responses were assessed by the isolation of organisms in cell culture, detection of TWAR DNA in lung tissues by PCR, and lung histology. Both regimens were effective in clearing infections induced by AR-388 (P = 0.02 and 0.007 for doxycycline and azithromycin, respectively) compared with controls. TWAR DNA was detected in 77 and 25% of culture-negative lungs 2 weeks after treatment of AR-388 and AR-39 infections, respectively. Histological changes showed interstitial pneumonitis and were similar over time for all groups. Single-dose azithromycin produced drug levels in lung tissues above the MICs for the test strains for a period three times longer than that of single-dose doxycycline. We concluded that short-term antibiotic regimens were successful for the treatment of experimental TWAR pneumonitis in mice. TWAR DNA was frequently recovered from lung tissues after apparently successful treatment.

Studies using monoclonal antibodies have demonstrated species-specific reactivities with Chlamydia pneumoniae. In this study, further characterization of C. pneumoniae specific monoclonal antibodies TT-205 and RR-402 and description of C. pneumoniae specific antibodies prepared against other isolates are presented. TT-205 and RR-402 were shown to neutralize infectivity. Neutralization in cell culture was specific and enhanced by complement. Attempts to characterize the reactive antigen by immunoblotting, immunoaffinity chromatography and radioimmunoprecipitation were unsuccessful, probably due to difficulties in solubilizing the immunoreactive epitope without denaturing it. Recognition of the determinant by the monoclonal antibodies is labile to physical and chemical treatments suggesting that the reactive epitope is conformational.

Chlamydia pneumoniae is a human respiratory pathogen. Unlike the other two Chlamydia species, no species-specific antigen has been defined for C. pneumoniae. An immunoreactive clone containing a 0.8-kb fragment was isolated from a C. pneumoniae (AR-39) genomic library by using anti-C. pneumoniae rabbit immune serum. By Southern hybridization analysis of chromosomal digests of the different Chlamydia spp., the 0.8-kb fragment was shown to react specifically with C. pneumoniae. Subcloning of this fragment into the pGEX-1 lambda T expression vector resulted in the expression of a 62-kDa fusion protein. This fusion protein as well as the cleaved C. pneumoniae peptide were recognized by anti-C. pneumoniae rabbit immune serum, while the glutathione S-transferase moiety was not recognized. The fusion protein was used to produce monospecific rabbit antiserum. This antiserum was shown to react with a 76-kDa protein in all C. pneumoniae isolates tested, specifically recognize C. pneumoniae inclusions in tissue culture, and neutralize infectivity of C. pneumoniae in cell culture. No reactivity was observed with Chlamydia trachomatis or Chlamydia psittaci. To isolate the entire coding sequence of the 76-kDa protein, two partially overlapping fragments of C. pneumoniae DNA, a 3.2-kb HindIII fragment and a 1.2-kb PvuII fragment, were isolated, cloned, and sequenced. No significant sequence similarity was found with any previously reported nucleotide or amino acid sequence of the other Chlamydia species. This C. pneumoniae protein containing a species-specific epitope could play a role in pathogenesis and may be useful as a diagnostic tool.

Background We have reported that the major outer membrane of C trachomatis is glycosylated and the glycan is a high mannose oligosaccharide. Cumulative studies have demonstrated that the glycan is important in attachment and infectivity through binding to the mannose receptor (MR). Glycan removal decreases infectivity in vitro and in vivo and simultaneous administration of mannan, a ligand of the MR, abrogates C trachomatis infection in a mouse model of pneumonitis. Thus, we are investigating the feasibility of an anti-adhesive therapy to prevent C trachomatis infection by identifying oligosaccharides that are effective in inhibiting infection in vitro and testing their efficacy in a mouse model of genital tract infection. Methods HeLa 229 cell monolayers were pretreated with serial concentrations of oligosaccharides prior to infection with C trachomatis. Neutralisation of infectivity was scored as >50% inhibition. For animal experiments, 8-week-old Swiss Webster female mice were primed with subcutaneous injections of Depo-Provera 1 week prior to challenge. Subsequently, mice were inoculated intravaginally with carbohydrates or PBS (n=5 mice per group) 30 min prior to infection with C trachomatis. Vaginal swab samples were obtained at 24, 48, and 72 h. post-infection, at peak times of shedding. Statistical significance was determined by the Student9s t test. Results Carbohydrates have been tested in vitro in hapten inhibition experiments against three serovars (D, E, F) most frequently isolated from genital tract infection. At the highest concentration tested, 4-nitrophenyl-α-D-mannopyranoside inhibited infectivity by 91%–92%; α-D-mannose-PAA from 77 to 93%; hen ovalbumin by 85%–89%; mannan by 77%–83%; and the high mannose fraction prepared from ovalbumin by 59%–98%. To determine efficacy in vivo, Swiss Webster mice were inoculated with different concentrations of inhibitors. Of those tested thus far, shedding of organism was significantly decreased (p Conclusions These preliminary studies suggest the potential feasibility for developing an “anti-adhesive therapy” as an alternate topical microbicide approach to prevent C trachomatis genital tract infection.

The antigen-specific serological response to Chlamydia pneumoniae was studied in 45 adults with coronary artery atherosclerosis and compared with that in 40 adults with acute respiratory infection. C. pneumoniae antigen and DNA were detected in lesions more frequently in patients with low immunoglobulin G titers against C. pneumoniae than in those with high immunoglobulin G titers. Reactivities with the 42-kDa (46%) and 52-kDa (31%) proteins were observed more frequently in sera from seropositive individuals with atherosclerosis than in sera from patients with acute respiratory infection. Antibodies against the C. pneumoniae-specific 42- and/or 52-kDa protein may be a marker for chronic C. pneumoniae infection.

Chlamydia pneumoniae is a human respiratory pathogen that causes acute respiratory disease and approximately 10% of community-acquired pneumonia. The infections are geographically widespread. Antibody prevalence studies have shown that virtually everyone is infected with the C. pneumoniae organisms at some time and that reinfection is common. In addition to respiratory disease, seroepidemiologic studies have shown an association of this organism with coronary artery disease. C. pneumoniae was detected in coronary artery atheromas by immunocytochemistry (15/36) and by polymerase chain reaction (PCR) (13/30) in 20 of 36 autopsy cases from Johannesburg, South Africa. Sequence analysis of the C. pneumoniae rRNA genes amplified by PCR confirmed that the amplified gene products were C. pneumoniae. Electron microscopy revealed typical pear-shaped C. pneumoniae elementary bodies in 6 of 21 atheromatous plaques. These findings support the seroepidemiologic studies and offer further evidence that C. pneumoniae may be involved in the atherosclerotic process.

Chlamydia pneumoniae is commonly detected in atherosclerotic plaque but the frequency of detection in non-cardiovascular (CV) tissues has not been well determined. In this study, archival autopsy tissue specimens from both CV and non-CV sites from 38 patients were tested by polymerase chain reaction and immunocytochemistry to detect C. pneumoniae. In addition, 33 surgical granuloma biopsy specimens were also tested. C. pneumoniae was detected most frequently in coronary artery tissue (34%) but was also detected in specimens from lung (13%), liver (10%), spleen (5%), bone marrow (10%), and lymph node (8%). The organism was detected in 3 of 33 granuloma specimens. These findings suggest that C. pneumoniae demonstrates a tropism for CV tissues and is either not widely distributed to non-CV tissues or does not persist chronically in those tissues after initial infection.

The human serological response was analyzed by using sera from patients who were serologically positive but isolation negative for Chlamydia pneumoniae and from patients with proven C. pneumoniae infection based on serology and isolation. To assess whether seroreactivity to C. pneumoniae proteins had potential diagnostic value, the cross-reactivities of these sera to other Chlamydia species and of sera from patients infected with C. trachomatis and C. psittaci to C. pneumoniae proteins were determined. In all serum samples from patients with proven C. pneumoniae infections, reactivities were seen with 98-, 68-, 60-, 39.5-, and 30-kilodalton proteins. Similar patterns were seen in sera from patients who were serologically positive and isolation negative. The onset of seropositivity for C. pneumoniae was accompanied by reactivities against presumably shared chlamydial antigens and a C. pneumoniae-specific 98-kilodalton protein.

Several isolates of Chlamydia pneumoniae were compared with each other and to Chlamydia trachomatis and Chlamydia psittaci by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblots. Protein profiles of the C. pneumoniae isolates appeared to be the same and were distinct from the other Chlamydia species. A 39.5-kilodalton (kDa) protein, similar in molecular weight to the major outer membrane proteins (MOMP) of C. trachomatis and C. psittaci, was found in the Sarkosyl-insoluble fraction, demonstrating its association with the outer membrane complex. In the outer membrane complex, the MOMP was shown to exist in disulfide-linked protein complexes. Electron microscopy of the Sarkosyl-extracted elementary bodies showed that the structural rigidity and pear-shaped morphology remained intact. Rabbit immune sera prepared against C. pneumoniae demonstrated immunoreactive proteins of 98-, 77-, 75-, 66-, 60-, 39.5-, 28-, and 17.5-kDa proteins. Cross-reactivity experiments revealed that most of the antigenic reactivities shared between C. psittaci and C. trachomatis extend to C. pneumoniae and that the 98-kDa protein recognition appeared to be C. pneumoniae specific. In contrast to the other Chlamydia spp., the recognition of the C. pneumoniae MOMP by homologous immune sera was weak and was cross-reactive with the MOMPs of the other Chlamydia species. These results suggest that the C. pneumoniae MOMP is less immunogenic and antigenically complex than are the MOMPs of C. trachomatis and C. psittaci.

To study persistent infection, reactivation of Chlamydia pneumoniae lung infection in mice was attempted by immunosuppression with cortisone treatment. Four-week-old Swiss-Webster mice were treated with cortisone acetate (125 mg/kg) every other day for a total of six doses, starting on day 28 after intranasal inoculation of C. pneumoniae AR-39. C. pneumoniae was recovered from the lungs in 6 of 13 animals after six doses of cortisone, while control animals given saline remained negative. C. pneumoniae DNA was detected by polymerase chain reaction in the 6 culture-positive mice and 2 of 10 controls. The presence of pathogen DNA in this animal model suggested viable organisms in a culture-negative state.