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Ronald J Harbeck

Publications and source records attributed to Ronald J Harbeck.

13 recordsLinked to original sources
PubMed2006

Repeated respiratory Mycoplasma pneumoniae infections in mice: effect of host genetic background.

Respiratory Mycoplasma pneumoniae (Mp) infection is involved in several acute and chronic lung diseases including community-acquired pneumonia, asthma and chronic obstructive pulmonary disease. In the chronic disease process, recurrent respiratory bacterial infections could occur, which may result in varying degrees of symptoms and lung inflammation among patients. However, the lung immunologic differences of host responses to repeated bacterial (i.e., Mp) infections remain to be determined. In the present study, we examined cellular and humoral responses to multiple (up to 3) Mp infections in two genetically different strains of mice (BALB/c and C57BL/6). Mice were intranasally inoculated with one Mp infection, two or three Mp infections (4 weeks apart), and sacrificed on days 3, 7 and 14 after the last Mp infection. Overall, compared to C57BL/6 mice, BALB/c mice demonstrated a significantly higher degree of lung tissue inflammatory cell infiltrate, BAL cellularity, and release of pro-inflammatory cytokines (TNF-alpha, keratinocyte-derived chemokine (KC, a mouse homolog of human chemokine Gro-alpha [CXCL1], and IFN-gamma). In addition, BALB/c mice presented higher levels of serum Mp-specific IgG and IgM, but not IgA. Consistently with lung and serum data, Mp load in BAL and lung specimens was significantly higher in BALB/c mice than C57BL/6 mice. Moreover, repeated Mp infections in BALB/c, but not C57BL/6 mice, produced a greater inflammatory response than did a single Mp infection. Our results suggest that hosts with different genetic background may have different susceptibility to repeated respiratory Mp infections along with inflammatory responses.

Animals↗
PubMed2006

Chronic urticaria sera increase basophil CD203c expression.

BACKGROUND: Approximately 40% of patients with chronic idiopathic urticaria have antibodies to the alpha subunit of the high-affinity IgE receptor. CD203c is a basophil activation marker known to be upregulated by cross-linking of the FcepsilonRIalpha receptor and may serve as a useful marker to identify these patients. OBJECTIVE: The primary objective was to assess the affect of sera from patients with chronic idiopathic urticaria on basophil CD203c expression. Secondary objectives were to correlate CD203c expression with basophil histamine release and size of the autologous serum skin test and to determine whether the mechanism is mediated by an IgG antibody. METHODS: Sera were obtained from patients with chronic idiopathic urticaria and positive autologous serum skin test or negative autologous serum skin test and normal controls. Sera were incubated with donor whole blood. Activated basophils from whole blood were identified by flow cytometry on the basis of the presence of CD203c on high-expressing IgE positive cells. RESULTS: Incubation of donor basophils with sera from patients with chronic idiopathic urticaria and positive autologous serum skin test demonstrated significant upregulation of CD203c. IgG depletion of representative sera from patients with chronic idiopathic urticaria resulted in significant decrease in CD203c expression on donor basophils. CD203c expression correlated with basophil histamine release and the size of the autologous serum skin test. CONCLUSION: Sera from patients with chronic idiopathic urticaria and positive autologous serum skin test significantly upregulate basophil CD203c and correlate with basophil histamine release. CLINICAL IMPLICATIONS: This article describes an activation marker on basophils whose expression is increased by sera from patients with chronic idiopathic urticaria.

Adult↗
PubMed2006

Interaction between cigarette smoke and mycoplasma infection: a murine model.

Cigarette smoke has a major impact on health issues worldwide. Although genetics certainly is a factor in the sensitivity to cigarette smoke, other lung environmental factors, such as infection, potentially could interact with cigarette smoke to induce inflammatory changes associated with various diseases. Four groups of BALB/c mice (smoking only; smoking + M. pneumoniae infection; mycoplasma only; saline control) were studied for eight weeks to determine the interactive outcomes of inflammation and structural changes in the smoking plus mycoplasma group. This group did have significantly higher amounts of neutrophil degranulation in the outer airway wall area (smooth muscle to alveolar attachments) (p = 0.03) and mRNA expression of matrix metalloproteinase-9 (p= 0.045). Although there was not a significant difference in alveolar tissue elastin between the groups, the smoking plus mycoplasma group had a level approximately 20% below the other groups. Even in this relatively short duration study, it appears that an infectious process can interact with cigarette smoke to produce a destructive type of inflammatory response (activated neutrophils and metalloproteinase-9) seen in the outer airway wall area.

Animals↗
PubMed2005

TLR2 signaling is critical for Mycoplasma pneumoniae-induced airway mucin expression.

Excessive airway mucin production contributes to airway obstruction in lung diseases such as asthma and chronic obstructive pulmonary disease. Respiratory infections, such as atypical bacterium Mycoplasma pneumoniae (Mp), have been proposed to worsen asthma and chronic obstructive pulmonary disease in part through increasing mucin. However, the molecular mechanisms involved in infection-induced airway mucin overexpression remain to be determined. TLRs have been recently shown to be a critical component in host innate immune response to infections. TLR2 signaling has been proposed to be involved in inflammatory cell activation by mycoplasma-derived lipoproteins. In this study, we show that TLR2 signaling is critical in Mp-induced airway mucin expression in mice and human lung epithelial cells. Respiratory Mp infection in BALB/c mice activated TLR2 signaling and increased airway mucin. A TLR2-neutralizing Ab significantly reduced mucin expression in Mp-infected BALB/c mice. Furthermore, Mp-induced airway mucin was abolished in TLR2 gene-deficient C57BL/6 mice. Additionally, Mp was shown to increase human lung A549 epithelial cell mucin expression, which was inhibited by the overexpression of a human TLR2 dominant-negative mutant. These results clearly demonstrate that respiratory Mp infection increases airway mucin expression, which is dependent on the activation of TLR2 signaling.

Animals↗
PubMed2005

Mycoplasma pneumoniae infection increases airway collagen deposition in a murine model of allergic airway inflammation.

Mycoplasma pneumoniae (Mp) has been linked to chronic asthma. Airway remodeling (e.g., airway collagen deposition or fibrosis) is one of the pathological features of chronic asthma. However, the effects of respiratory Mp infection on airway fibrosis in asthma remain unclear. In the present study, we hypothesized that respiratory Mp infection may increase the airway collagen deposition in a murine model of allergic airway inflammation in part through upregulation of transforming growth factor (TGF)-beta1. Double (2 wk apart) inoculations of Mp or saline (control) were given to mice with or without previous allergen (ovalbumin) challenges. On days 14 and 42 after the last Mp or saline, lung tissue and bronchoalveolar lavage (BAL) fluid were collected for analyses of collagen and TGF-beta1 at protein and mRNA levels. In allergen-naïve mice, Mp did not alter airway wall collagen. In allergen-challenged mice, Mp infections did not change airway wall collagen deposition on day 14 but increased the airway collagen on day 42; this increase was accompanied by increased TGF-beta1 protein in the airway wall and reduced TGF-beta1 protein release from the lung tissue into BAL fluid. Our results suggest that Mp infections could modulate airway collagen deposition in a murine model of allergic airway inflammation with TGF-beta1 involved in the collagen deposition process.

Animals↗
PubMed2005

Aerosolized sodium hypochlorite inhibits viability and allergenicity of mold on building materials.

BACKGROUND: Commercial and residential buildings can become contaminated with molds, which may trigger allergic disorders. Mold remediation efforts may require costly replacement of mold-contaminated building materials. Disinfectants that contain dilute sodium hypochlorite can kill mold and are practical to use. Whether they also inhibit mold allergy symptoms is unknown. OBJECTIVE: We tested the hypothesis that sodium hypochlorite-containing spray products kill Aspergillus fumigatus and inhibit A fumigatus allergens. METHODS: A fumigatus was grown on 3 common building construction materials, as well as in solution by conventional laboratory methods. Two sodium hypochlorite-containing household products (diluted bleach and Tilex) were sprayed on the mold-contaminated materials or added to mold in solution and compared with untreated controls. Surface mold and associated debris were mechanically removed from treated and untreated boards. Conidia in the extracted board materials were quantified by light microscopy, examined for morphologic changes by scanning electron microscopy, and cultured for viable mold. Extracts were tested for A fumigatus antigen by ELISA, and for A fumigatus allergen by skin prick testing using extracts prepared from both the boards and the cultured solutions. RESULTS: Both sodium hypochlorite disinfectants killed A fumigatus in solution and on mold-contaminated building materials. Light microscopy and scanning electron microscopy demonstrated changes to the conidial surface. Both dilute bleach and Tilex inhibited A fumigatus recognition by ELISA. Skin testing supported the results of the ELISAs and demonstrated loss of skin test reactivity to the sodium hypochlorite-treated mold solutions in most of the subjects. Of the 4 individuals who had a positive skin test result to mold grown on oriented strand board building material, 3 no longer reacted to extracts from bleach-treated boards. CONCLUSION: Spray application of sodium hypochlorite-containing disinfectants onto mold-contaminated building material kills A fumigatus, modifies the surface characteristics of A fumigatus conidia, reduces recognition of A fumigatus mold by ELISA, and results in loss of skin test reactivity to the treated mold in individuals allergic to A fumigatus.

Air Pollution, Indoor↗
PubMed2004

Surfactant protein A binds Mycoplasma pneumoniae with high affinity and attenuates its growth by recognition of disaturated phosphatidylglycerols.

Surfactant Protein A (SP-A) is an abundant, multifunctional lectin that resides within the bronchoalveolar compartment of the lung and plays an important role in the innate immunity of the organ. Mycoplasma pneumoniae is a human pathogen that resides in the same compartment as SP-A, and we examined the interaction between the two. Preparations of human and rat SP-A recognized the mycoplasma with high affinity in the presence of Ca(2+), exhibiting apparent K(')(d) values in the nanomolar range. Membranes prepared from the microbe also bound human and rat SP-A with similar characteristics and affinity to the intact cells. The ligand for SP-A was insensitive to proteolysis. Lipid extracts prepared from the mycoplasma, bound SP-A with high affinity when examined by ligand blot analysis. These lipid extracts were also potent competitive inhibitors (IC(50) = 0.2 nM) of human SP-A binding to mycoplasma membranes. The major lipid ligands for the protein identified by mass spectrometry are a group of disaturated phosphatidylglycerols. The addition of SP-A to cultures of M. pneumoniae markedly attenuated the growth of the organism assessed by colony formation, metabolic activity, and DNA replication. The bacteriostatic effects of SP-A were reversed by dipalmitoylphosphatidylglycerol. These findings demonstrate that human SP-A can play a direct role in antibody-independent immunity to M. pneumoniae by interacting with lipid ligands expressed on the surface of the organism and implicate SP-A in the immediate host response to the bacteria.

Animals↗
PubMed2004

Inhaled fluticasone propionate reduces concentration of Mycoplasma pneumoniae, inflammation, and bronchial hyperresponsiveness in lungs of mice.

BACKGROUND: Mycoplasma pneumoniae has been shown to induce airway inflammation and bronchial hyperresponsiveness (BHR) in mice. Inhaled corticosteroids are the mainstay of asthma treatment, but their effects on M. pneumoniae and associated airway inflammation and BHR are poorly understood. METHODS: Four groups of mice were studied to determine whether inhaled fluticasone propionate (FP) could attenuate airway inflammation and BHR by reducing or eliminating M. pneumoniae in lungs. The active group received aerosolized FP once daily for 5 days. Control mice received aerosolized sham solution plus M. pneumoniae, sham solution alone, or FP alone. RESULTS: Mice treated with sham solution or FP alone did not develop airway inflammation or BHR. Mice infected with M. pneumoniae (no FP) developed significant lung inflammation and BHR. FP treatment of infected mice reduced neutrophils in bronchoalveolar lavage fluid (BALF), lung inflammation, and BHR. Expression of Toll-like receptor 2 in lung tissue tended to be down-regulated (P=.18) by FP in infected mice. FP reduced M. pneumoniae by up to 20-fold in lung tissue but not in BALF. CONCLUSION: Inhaled FP suppresses airway inflammation and BHR, which may be caused, in part, by its ability to reduce concentrations of M. pneumoniae in lung tissue.

Administration, Inhalation↗
PubMed2003

Effects of respiratory Mycoplasma pneumoniae infection on allergen-induced bronchial hyperresponsiveness and lung inflammation in mice.

Airway mycoplasma infection may be associated with asthma pathophysiology. However, the direct effects of mycoplasma infection on asthma remain unknown. Using a murine allergic-asthma model, we evaluated the effects of different timing of airway Mycoplasma pneumoniae infection on bronchial hyperresponsiveness (BHR), lung inflammation, and the protein levels of Th1 (gamma interferon [IFN-gamma]) and Th2 (interleukin 4 [IL-4]) cytokines in bronchoalveolar lavage fluid. When mycoplasma infection occurred 3 days before allergen (ovalbumin) sensitization and challenge, the infection reduced the BHR and inflammatory-cell influx into the lung. This was accompanied by a significant induction of Th1 responses (increased IFN-gamma and decreased IL-4 production). Conversely, when mycoplasma infection occurred 2 days after allergen sensitization and challenge, the infection initially caused a temporary reduction of BHR and then increased BHR, lung inflammation, and IL-4 levels. Our data suggest that mycoplasma infection could modulate both physiological and immunological responses in the murine asthma model. Our animal models may also provide a new means to understand the role of infection in asthma pathogenesis and give evidence for the asthma hygiene hypothesis.

Allergens↗
PubMed2003

Lysophosphatidylcholines prime the NADPH oxidase and stimulate multiple neutrophil functions through changes in cytosolic calcium.

A mixture of lysophosphatidylcholines (lyso-PCs) are generated during blood storage and are etiologic in models of acute lung injury. We hypothesize that lyso-PCs stimulate polymorphonuclear neutrophils (PMNs) through Ca(2)(+)-dependent signaling. The lyso-PC mix (0.45-14.5 micro M) and the individual lyso-PCs primed formyl-Met-Leu-Phe (fMLP) activation of the oxidase (1.8- to 15.7-fold and 1.7- to 14.8-fold; P<0.05). Labeled lyso-PCs demonstrated a membrane association with PMNs and caused rapid increases in cytosolic Ca(2)(+). Receptor desensitization studies implicated a common receptor or a family of receptors for the observed lyso-PC-mediated changes in PMN priming, and cytosolic Ca(2)(+) functions were pertussis toxin-sensitive. Lyso-PCs caused rapid serine phosphorylation of a 68-kD protein but did not activate mitogen-activated protein kinases or cause changes in tyrosine phosphorylation. With respect to alterations in PMN function, lyso-PCs caused PMN adherence, increased expression of CD11b and the fMLP receptor, reduced chemotaxis, provoked changes in morphology, elicited degranulation, and augmented fMLP-induced azurophilic degranulation (P<0.05). Cytosolic Ca(2)(+) chelation inhibited lyso-PC-mediated priming of the oxidase, CD11b surface expression, changes in PMN morphology, and serine phosphorylation of the 68-kD protein. In conclusion, lyso-PCs affect multiple PMN functions in a Ca(2)(+)-dependent manner that involves the activation of a pertussis toxin-sensitive G-protein.

CD11 Antigens↗
PubMed2002

Human surfactant protein D (SP-D) binds Mycoplasma pneumoniae by high affinity interactions with lipids.

Increasing evidence now identifies surfactant protein D (SP-D) as an important element of the innate immune system of the lung. In this study, we examined the interactions of rat and human SP-D with the human pathogen, Mycoplasma pneumoniae. Rat and human SP-D bound the organism with high affinity in a reaction that required Ca(2+) and was inhibited by EGTA. Membranes derived from the organism bound the proteins in a similar manner, except the rat SP-D also exhibited a significant level of Ca(2+)-independent binding. Pretreatment of membranes with proteases did not alter the Ca(2+)-dependent SP-D binding of membranes by either protein. Mannose, glucose, maltose, and inositol, at millimolar concentrations, competed for human SP-D binding to the bacterial membrane. Lipids extracted from membranes and separated by two-dimensional thin layer chromatography bound human SP-D with high affinity in a Ca(2+)-dependent reaction. A tandem mutant of SP-D with E321Q and N323D substitutions, failed to bind M. pneumoniae lipids, directly implicating the carbohydrate recognition domain in the interaction. The interaction of rat and human SP-D with M. pneumoniae was unaffected by the presence of surfactant lipids and the hydrophobic surfactant proteins. These findings demonstrate that M. pneumoniae is likely to be recognized by SP-D in the alveolar environment and that primary determinants recognized on the organism are lipid components of the cell membrane.

Animals↗