Bacterial DNA in house and farm barn dust

Roy, Sitesh R.; Schiltz, A.M.; A, Marotta; Shen, Yanqin; Liu, Andrew H.

doi:10.1016/s0091-6749(03)01863-3

Cited by 91 publications

(57 citation statements)

References 56 publications

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“…49 These methylated cytosine-phosphate-guanine motifs have been found in dust from farm homes and barns; the collected dust synergistically enhances the in vitro effects of endotoxin on peripheral blood leukocytes. 50 Very little is known about airborne concentra-tions, and even less is known about the effects on human disease; however, because the concentrations of bacterial methylated cytosine-phosphate-guanine motifs in settled dust correlate with endotoxin concentrations, it is possible that bacterial methylated cytosine-phosphate-guanine motifs are partly responsible for the immunomodulatory effects of endotoxin. 50 …”

Section: Pathogen-associated Molecular Patternsmentioning

confidence: 99%

“…50 Very little is known about airborne concentra-tions, and even less is known about the effects on human disease; however, because the concentrations of bacterial methylated cytosine-phosphate-guanine motifs in settled dust correlate with endotoxin concentrations, it is possible that bacterial methylated cytosine-phosphate-guanine motifs are partly responsible for the immunomodulatory effects of endotoxin. 50 …”

Section: Pathogen-associated Molecular Patternsmentioning

confidence: 99%

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Complex Interactions of Pollutant and Allergen Exposures and Their Impact on People With Asthma

Eggleston

2009

Pediatrics

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Pediatric asthma has many causes and can manifest differently in different children and at different times. Understanding the many factors related to the development and exacerbation of asthma is complicated by the complexity of the many environmental exposures related to asthma development and morbidity. Furthermore, the same environmental exposures that may cause increased symptoms at 1 point in time may be protective when the exposure occurs earlier or at high enough levels. We know that environmental exposures such as allergens, irritants, and pollutants are quite complex in their composition; further examination of this complexity may improve our understanding of this complex and highly prevalent disease. Pediatrics 2009;123:S160-S167 I N THE PAST 20 years, we have begun to understand that airway inflammation in asthma arises from maladaptation to environmental stresses. In studying this process, we have tended to focus on one mechanism or another (eg, immunoglobulin E [IgE]-mediated responses to biological materials or oxidative stress resulting from ozone or particulates) and have found evidence that each is important. Patients encounter these environmental stresses simultaneously, however, and this simultaneous exposure may enhance responses (ie, adjuvant or priming) or may decrease responses to one of the stressors. We have begun to address the issue of complex responses to simultaneous exposure to other bioactive materials in the hygiene hypothesis. 1,2 Originally, this hypothesis proposed that the increased prevalence of allergic diseases was related to a population shift in immune responsiveness because infectious illnesses were less prevalent. More recently, researchers found that children had less asthma and allergic disease when they were exposed early in life to endotoxin from Gram-negative bacteria, 2 a finding that seems to confirm the hygiene hypothesis. This finding, however, could also be an example of effect modification (ie, simultaneous exposure to endotoxin in airborne particulates decreased IgE-mediated sensitization to allergens). ENVIRONMENTAL ALLERGENS ARE CARRIED ON PARTICLESOur understanding of environmental allergen exposure depends on continually developing technology that allows us to measure levels of allergenic proteins in the environment. Technological advances have made it possible to test the hypotheses that environmental allergen exposure is related to sensitization, asthma prevalence and severity, and asthma incidence rates. In addition, asthma prevalence and severity have clear dose-response relationships to allergen exposure. Indoor allergen levels measured both in settled household dust and in indoor air are more clearly related to asthma than are outdoor allergen levels 3 ; therefore, many of the data supporting a discussion of interactions between allergens and pollutants refer to indoor allergen exposure. An important corollary of those studies is the demonstration that allergens carried on airborne particles have clearly defined characteristics that are rel...

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Section: Pathogen-associated Molecular Patternsmentioning

confidence: 99%

Section: Pathogen-associated Molecular Patternsmentioning

confidence: 99%

Complex Interactions of Pollutant and Allergen Exposures and Their Impact on People With Asthma

Eggleston

2009

Pediatrics

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“…Evidence from cohorts of farm children have shown that increased exposure to lipopolysaccharide (LPS) is a protective factor against allergy (7). Other TLRs can also have a protective effect against the development of asthma; polymorphisms in the TLR9 promoter region, which may affect expression levels, for example, by altering NF-B binding (22), have been associated with wheeze in later life (8,28), and levels of CpG oligodeoxynucleotides are greater in dust from rural homes (25). In a murine model, CpG treatment protects neonatal mice from the development of allergy (6).…”

mentioning

confidence: 99%

Preexposure to CpG Protects against the Delayed Effects of Neonatal Respiratory Syncytial Virus Infection

Yamaguchi

Harker

Wang

et al. 2012

J Virol

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Severe respiratory viral infection in early life is associated with recurrent wheeze and asthma in later childhood. Neonatal immune responses tend to be skewed toward T helper 2 (Th2) responses, which may contribute to the development of a pathogenic recall response to respiratory infection. Since neonatal Th2 skewing can be modified by stimulation with Toll-like receptor (TLR) ligands, we investigated the effect of exposure to CpG oligodeoxynucleotides (TLR9 ligands) prior to neonatal respiratory syncytial virus (RSV) infection in mice. CpG preexposure was protective against enhanced disease during secondary adult RSV challenge, with a reduction in viral load and an increase in Th1 responses. A similar Th1 switch and reduction in disease were observed if CpG was administered in the interval between neonatal infection and challenge. In neonates, CpG pretreatment led to a transient increase in expression of major histocompatibility complex class II (MHCII) and CD80 on CD11c-positive cells and gamma interferon (IFN-γ) production by NK cells after RSV infection, suggesting that the protective effects may be mediated by antigen-presenting cells (APC) and NK cells. We conclude that the adverse effects of early-life respiratory viral infection on later lung health might be mitigated by conditions that promote TLR activation in the infant lung.

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“…In our meta-analysis of 16 pertinent studies, the OR for allergen sensitization was 0.85 (CI 0.77-0.93) for infants raised in homes with high ambient endotoxin levels versus those raised in low levels [11] . In consideration of these relatively weak associations, it is important to recognize that endotoxin-rich environments generally contain increased levels of other immunostimulatory microbial products [15,16] . Furthermore, several manmade pollutants promote development of allergic hypersensitivities [17] .…”

mentioning

confidence: 99%

Regulation of Aeroallergen Immunity by the Innate Immune System: Laboratory Evidence for a New Paradigm

Horner

2009

J Innate Immun

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Over the last decade, it has become increasingly clear that innate responses to microbes are mediated largely by toll-like receptors (TLRs), which recognize a diverse family of molecules produced by viruses, bacteria and fungi. This article will present evidence that TLRs also play a dominant role in innate responses to non-infectious immunostimulatory materials present in house dust extracts (HDEs) and the living environments they represent. However, our investigations challenge the commonly held view that microbial products in ambient air protect against the allergic march by promoting protective Th1 biased responses to inspired aeroallergens. Instead, all HDEs studied to date have preferentially promoted the development of Th2 biased airway hypersensitivities when used as adjuvants for intranasal (i.n.) vaccination. In contrast, daily low dose i.n. HDE delivery was found to promote the development of aeroallergen tolerance. This article will review these experimental findings as evidence to propose a new paradigm by which airborne TLR ligands and other stimulants of innate immunity may influence aeroallergen specific immunity and the genesis of allergic respiratory diseases.

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Bacterial DNA in house and farm barn dust

Cited by 91 publications

References 56 publications

Complex Interactions of Pollutant and Allergen Exposures and Their Impact on People With Asthma

Complex Interactions of Pollutant and Allergen Exposures and Their Impact on People With Asthma

Preexposure to CpG Protects against the Delayed Effects of Neonatal Respiratory Syncytial Virus Infection

Regulation of Aeroallergen Immunity by the Innate Immune System: Laboratory Evidence for a New Paradigm

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