We express our gratitude to the children and families of the COPSAC2010 cohort study for all their support and commitment. We acknowledge and appreciate the unique efforts of the COPSAC research team and the technical help from Technician Lisbeth Buus Rosholm, Technical University of Denmark, for the measurement of cytokines and chemokines.

The studies were conducted in accordance with the guiding principles of the Declaration of Helsinki. Approvals from the Ethics Committee for Copenhagen (KF 01-289/96 for COPSAC2000 and H-B-2008-093 for COPSAC2010) and the Danish Data Protection Agency were obtained, and written informed consent was obtained from both parents of each subject before enrollment.
1. Experimental Setup
<ol>
	<li>Use sheets of filter paper (fibrous hydroxylated-polyester sheets, see the Table of Materials)6,7.
	<ol>
		<li>Cut out strips 3&#160;x 15 mm in size for a 1-month-old child and in an L-shape for older children and adults (5&#160;x 20&#160;x 10 mm (short arm of the L)).</li>
	</ol>
	</li>
	<li>Insert one piece of filter paper into each nostril of an infant using forceps. Place the filter paper at the anterior part of the inferior turbinate (approximately 1 cm inside the nostril for neonates and 1.5 cm for all other ages).
	<ol>
		<li>Place neonates on a bed and give them sugar water for comfort. 
		NOTE: For children of all other ages, the sampling is performed most easily with the subject seated on a chair.</li>
		<li>For older children, insert the long arm of the L-shaped filter paper into each nostril.</li>
	</ol>
	</li>
	<li>Apply a nose clip around the nostrils to minimize discomfort and to avoid the accidental loss of the filter paper.</li>
	<li>Remove the filter papers after 2 min of absorption.</li>
	<li>Place the filter papers in labeled tubes and freeze them immediately at -80 &#176;C.</li>
	<li>Make a note of any symptoms of airway infection shown by the child on the day of sampling.</li>
	<li>Record any sneezing, persistent crying, or epistaxis that occurs during the 2 min of sampling.</li>
</ol>
2. Quantification of Airway Immune-mediators
<ol>
	<li>Take up to 10 random samples from the freezer. Record the identification numbers. Keep the samples on ice during the whole working process.</li>
	<li>After thawing on ice, immerse the filter papers (per subject) from both nostrils in 300 &#181;L of freshly prepared buffer (see the Table of Materials) containing one complete protease inhibitor tablet (see the Table of Materials) per 25 mL of buffer.
	<ol>
		<li>Adjust the volume of buffer as per the size of the filter paper.
		<ol>
			<li>Use 300 &#181;L of buffer for filter papers 3&#160;x 15 mm in size.</li>
			<li>If only one filter paper is available, use half the buffer volume (150 &#181;L).</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Transfer the samples to a plate shaker (400 rpm) for 5 min. Use a timer.</li>
	<li>Transfer the moist filter papers and assay buffer into the cup of a cellulose acetate tube filter (0.22 &#181;m pore size) placed within a microcentrifuge tube (see the Table of Materials).</li>
	<li>Centrifuge at 16,000 x g for 5 min in a cooled centrifuge (at 4 &#176;C) to obtain filtered nasal extract in the tube.</li>
	<li>Remove the cup and keep the tubes on ice while aliquoting the nasal extract into the wells of low-protein binding storage plates (see the Table of Materials).</li>
	<li>Store at -80 &#176;C until analysis.</li>
	<li>Determine the concentrations of cytokines and chemokines in the nasal extracts using a high-sensitivity, electrochemiluminesce-based multiplexed array system (see the Table of Materials). 
	NOTE: A human 10-plex TH1/TH2 cytokine assay, 9-plex chemokine assay, and single-plex IL-17A, TGF-&#946;1, and TSLP were performed here.
	<ol>
		<li>For the assays, incubate the nasal extracts overnight at 4 &#176;C. Conduct the measurements as per the standard manufacturer protocol (see the Table of Materials). 
		NOTE: The immunoassays (see the Table of Materials) typically have a high dynamic range for measurement ranging between 1 &#38; 10,000 pg/mL, but for some assays, it can be 100,000 pg/mL. This means that all samples can be run at the same dilution, thus limiting the influence of dissimilar dilutions in healthy and diseased subjects, as is the case in other similar immunoassays. The lower limit of detection for all cytokines was 1 pg/mL or less, and for chemokines, it ranged between 1 &#38; 50 pg/mL. TSLP was not detectable in 98% of samples at 1 month of age.</li>
	</ol>
	</li>
</ol>
3. Statistics
<ol>
	<li>Log-transform the data prior to analysis to obtain normally distributed residuals of the cytokine and chemokine levels.</li>
	<li>If the samples are analyzed in more than one batch, correct the cytokine and chemokine data for batch-wise centering on the log-transformed data.
	<ol>
		<li>Incorporate the overall mean and anti-log transformation to obtain data in the original measurement units. 
		NOTE: For every set of analyses done, consider adjusting variables that affect the level of cytokines and chemokines. This could be maternal influences (e.g., alcohol consumption and smoking during pregnancy), breastfeeding, adverse events during sampling, siblings, pets in the home, etc.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Bousquet, J., van Cauwenberge, P., Khaltaev, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Allergic+Rhinitis+and+Its+Impact+on+Asthma.">Allergic Rhinitis and Its Impact on Asthma.</a> J Allergy Clin Immunol. 108 (5), 147-334 (2001).</li><li>Howarth, P. H., Persson, C. G. A., Meltzer, E. O., Jacobson, M. R., Durham, S. R., Silkoff, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Objective+monitoring+of+nasal+airway+inflammation+in+rhinitis.">Objective monitoring of nasal airway inflammation in rhinitis.</a> J Allergy Clin Immunol. 115 (3), 414-441 (2005).</li><li>Bensch, G. W., Nelson, H. S., Borish, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+cytokines+in+nasal+secretions+after+nasal+antigen+challenge:+lack+of+influence+of+antihistamines.">Evaluation of cytokines in nasal secretions after nasal antigen challenge: lack of influence of antihistamines.</a> Ann Allergy Asthma Immunol. 88 (5), 457-462 (2002).</li><li>Sussman, G. L., Mason, J., Compton, D., Stewart, J., Ricard, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+efficacy+and+safety+of+fexofenadine+HCl+and+pseudoephedrine,+alone+and+in+combination,+in+seasonal+allergic+rhinitis.">The efficacy and safety of fexofenadine HCl and pseudoephedrine, alone and in combination, in seasonal allergic rhinitis.</a> J Allergy Clin Immunol. 104 (1), 100-106 (1999).</li><li>Bisgaard, H., Robinson, C., R&#248;meling, F., Mygind, N., Church, M., Holgate, S. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leukotriene+C4+and+histamine+in+early+allergic+reaction+in+the+nose.">Leukotriene C4 and histamine in early allergic reaction in the nose.</a> Allergy. 43 (3), 219-227 (1988).</li><li>Chawes, B. L. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+method+for+assessing+unchallenged+levels+of+mediators+in+nasal+epithelial+lining+fluid.">A novel method for assessing unchallenged levels of mediators in nasal epithelial lining fluid.</a> J Allergy Clin Immunol. 125 (6), 1387-1389 (2010).</li><li>F&#0248;lsgaard, N. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenic+bacteria+colonizing+the+airways+in+asymptomatic+neonates+stimulates+topical+inflammatory+mediator+release.">Pathogenic bacteria colonizing the airways in asymptomatic neonates stimulates topical inflammatory mediator release.</a> Am J Respir Crit Care Med. 187 (6), 589-595 (2013).</li><li>F&#0248;lsgaard, N. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neonatal+Cytokine+Profile+in+the+Airway+Mucosal+Lining+Fluid+Is+Skewed+by+Maternal+Atopy.">Neonatal Cytokine Profile in the Airway Mucosal Lining Fluid Is Skewed by Maternal Atopy.</a> Am J Respir Crit Care Med. 185 (3), 275-280 (2012).</li><li>Chawes, B. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Vitamin+D3+Supplementation+During+Pregnancy+on+Risk+of+Persistent+Wheeze+in+the+Offspring:+A+Randomized+Clinical+Trial.">Effect of Vitamin D3 Supplementation During Pregnancy on Risk of Persistent Wheeze in the Offspring: A Randomized Clinical Trial.</a> JAMA. 315 (4), 353-361 (2016).</li><li>Bischoff, A. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Altered+Response+to+A(H1N1)pnd09+Vaccination+in+Pregnant+Women:+A+Single+Blinded+Randomized+Controlled+Trial.">Altered Response to A(H1N1)pnd09 Vaccination in Pregnant Women: A Single Blinded Randomized Controlled Trial.</a> PloS One. 8 (4), 56700 (2013).</li><li>Wolsk, H. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Picornavirus-Induced+Airway+Mucosa+Immune+Profile+in+Asymptomatic+Neonates.">Picornavirus-Induced Airway Mucosa Immune Profile in Asymptomatic Neonates.</a> J Infect Dis. 213 (8), 1262-1270 (2016).</li><li>Wolsk, H. M., Chawes, B. L., F&#248;lsgaard, N. V., Rasmussen, M. A., Brix, S., Bisgaard, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Siblings+Promote+a+Type+1/Type+17-oriented+immune+response+in+the+airways+of+asymptomatic+neonates.">Siblings Promote a Type 1/Type 17-oriented immune response in the airways of asymptomatic neonates.</a> Allergy. 71 (6), 820-828 (2016).</li><li>Alam, R., Sim, T. C., Hilsmeier, K., Grant, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+new+technique+for+recovery+of+cytokines+from+inflammatory+sites+in+situ.">Development of a new technique for recovery of cytokines from inflammatory sites in situ.</a> J Immunol Methods. 155 (1), 25-29 (1992).</li><li>Ishizaka, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+bronchoscopic+microsample+probe+to+measure+the+biochemical+constituents+in+epithelial+lining+fluid+of+patients+with+acute+respiratory+distress+syndrome.">New bronchoscopic microsample probe to measure the biochemical constituents in epithelial lining fluid of patients with acute respiratory distress syndrome.</a> Crit Care Med. 29 (4), 896-898 (2001).</li><li>Ishizaka, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elevation+of+KL-6,+a+lung+epithelial+cell+marker,+in+plasma+and+epithelial+lining+fluid+in+acute+respiratory+distress+syndrome.">Elevation of KL-6, a lung epithelial cell marker, in plasma and epithelial lining fluid in acute respiratory distress syndrome.</a> Am J Physiol Lung Cell Mol Physiol. 286 (6), 1088-1094 (2004).</li><li>Nakano, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelin-1+level+in+epithelial+lining+fluid+of+patients+with+acute+respiratory+distress+syndrome.">Endothelin-1 level in epithelial lining fluid of patients with acute respiratory distress syndrome.</a> Respirology. 12 (5), 740-743 (2007).</li><li>Komaki, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytokine-mediated+xanthine+oxidase+upregulation+in+chronic+obstructive+pulmonary+disease's+airways.">Cytokine-mediated xanthine oxidase upregulation in chronic obstructive pulmonary disease's airways.</a> Pulm Pharmacol Ther. 18 (4), 297-302 (2005).</li><li>Moeller, A., Franklin, P., Hall, G. L., Horak, F., Wildhaber, J. H., Stick, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+exhaled+breath+condensates+in+infants.">Measuring exhaled breath condensates in infants.</a> Pediatr Pulmonol. 41 (2), 184-187 (2006).</li></ol>

All authors declare no potential, perceived, or real conflict of interest regarding the content of this manuscript. The funding agencies did not have any role in the design and conduct of the study; the collection, management, and interpretation of the data; or the preparation, review, and approval of the manuscript. No pharmaceutical company was involved in the study.

With the technique presented here, we were able to determine the in vivo upper-airway mucosal immune profile in children from as early as 1 month of age, which has not been done previously. We observed that presence of specific airway bacteria and picornaviruses7,11, as well as other pre&#160;and perinatal exposures, were mirrored in the airway immune profile of the neonates. Furthermore, we used these airway immune profile data to study the mechanism of...

The mucosal lining fluid of the nose makes up the liquid part of the upper-airway system. It consists of a complex matrix of mediators derived from the interplay between the epithelium and the immune cells that make up the first line of defense against invading microorganisms. The nasal mucosa is easily accessible, and there is a strong functional and immunological relationship between the nose and the bronchi1. This compartment is of special interest in relation to airway diseases that are common in childhood, such as asthma and allergic rhinitis, but also to a range of other respiratory disorders more prevalent later in life.
Here, we describe the implementation of a method to sample undisturbed mucosal lining fluid from the nasal cavity using a filter paper-based, noninvasive technique, as well as a subsequent extraction procedure, used to elute protein-based analytes from the filter papers prior to their quantification. This technique can, for example, be used to obtain in vivo immune signatures of both healthy individuals and individuals with various respiratory diseases. Furthermore, it is possible to examine exposures of importance for a specific immune signature and to evaluate if it is a predictor or mediator of later disease development.
Mucosal lining fluid has previously been obtained by nasal lavage2, which is often preceded by a nasal challenge test, where an allergen is introduced in high levels to stimulate an inflammatory response3,4. However, the nasal lavage technique is not feasible in young children and introduces an unknown dilution factor, which confounds the outcomes, as the diluted mediator levels can fall below the detection limit of the assay5. Moreover, due to the unknown dilution factor, the measured analyte responses from the nasal challenge tests are not comparable between individuals, thereby limiting the usefulness of the nasal lavage technique in a cohort setting. Finally, allergen challenge is only applicable in sensitized subjects, and other challenges, such as the histamine challenge, are not physiologically relevant, potentially causing a ceiling effect on mediator release. These problems are circumvented in the presented filter paper-based technique for mucosal lining fluid collection, where the individual secretion of fluids and analyte levels are the only factors that influence inter-individual variance.
During the extraction procedure, analytes are eluted from the filter papers after the addition of identical volumes of buffer to all samples. This favors similar ex vivo dilution of all samples. An extraction buffer of albumin-based isotonic salt solution is used for the extraction step; it enables the extraction of protein-based mediators and stabilizes proteins to limit denaturation during the subsequent freezing of eluted proteins prior to quantification. To avoid protein degradation during the extraction phase, a cocktail of protease inhibitors is added to the extraction buffer.
The implementation of techniques that allow for the quantification of undisturbed, in vivo-generated immune mediators at mucosal sites is of the utmost importance. First, the mucosal site makes up the largest immunological organ in the body. Second, the nasal location is the primary site of airborne exposure and is tightly connected to the respiratory immunological compartment of the lungs1. Third, the possibility of surveying this important organ with a noninvasive technique opens the possibility to provide a plethora of information on the important microbe-immune interaction axis in relation to health and disease in the airways. Fourth, there are many other possible applications of this technique, such as studying local immunological alterations in randomized, controlled trials of drugs and micronutrients.
We initially implemented the technique in the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000) cohort, where we determined the immune profile of the mucosal lining fluid in 7-year-old children with allergic rhinitis versus healthy controls13. Subsequently, we successfully applied this technique to the longitudinal COPSAC2010 cohort and assessed airway immune profiles at 1 month, 2 years, and 6 years of age and at instances of acute respiratory symptoms. Results from the 1-month-old neonates have demonstrated important associations between the immune signature and early-life environmental exposure7,8,9,10,11,12.

<table border="0" cellpadding="0" cellspacing="0" width="1688">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">Fibrous hydroxylatedpolyester sheets</td>
			<td style="width:103px;">Accuwik Ultra&#160;</td>
			<td style="width:119px;">SPR0730</td>
			<td style="width:1084px;">Filter paper</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Milliplex Assay Buffer&#160;</td>
			<td>Millipore</td>
			<td>L-AB</td>
			<td>Buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">low-protein binding storage plates&#160;</td>
			<td>Thermo Scientific</td>
			<td>CLS8161</td>
			<td>Plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Protease Inhibitor</td>
			<td style="width:103px;">Roche</td>
			<td align="right" style="width:119px;">11873580001</td>
			<td>complete EDTA-free Protease Inhibitor Cocktail</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">Reader of multi-spot plates</td>
			<td style="width:103px;">Mesoscale</td>
			<td style="width:119px;">NA</td>
			<td>Sector imager 6000</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:383px;">Assays&#160;</td>
			<td style="width:103px;">Mesoscale</td>
			<td style="width:119px;"></td>
			<td>Human 10-plex TH1/TH2 cytokine assay and 9-plex chemokine assay, and singleplex IL-17A, TGF-&#946;1and TSLP. A description can be found online on www.mesoscale.com</td>
		</tr>
	</tbody>
</table>

noninvasive sampling of mucosal lining fluid for the quantification of in vivo upper airway immune-mediator levels

This protocol describes noninvasive sampling of undisturbed upper airway mucosal lining fluid. It also details the extraction procedure used prior to the analysis of immune mediators in fluid eluates for the study of the airway topical immune signature, without the need for stimulation procedures (often used by other techniques). The mucosal lining fluid is sampled on a strip of filter paper placed at the anterior part of the inferior turbinate and left for 2 min of absorption. Analytes are eluted from the filter papers, and the extracted protein-based eluates are analyzed by an electrochemiluminescence-based immunoassay, allowing for the high-sensitivity quantification of low- and high-level analytes in the same sample. We measured the in vivo levels of 20 preselected immune mediators related to specific immune signaling pathways in the upper airway mucosa, but the technique is not limited to that specific panel or sampling site. The technique was first implemented in 7-year-old children from the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000) cohort with allergic rhinitis. It was thereafter used in the longitudinal COPSAC2010 birth cohort, sampled at 1 month, 2 years, and 6 years of age and at instances of acute respiratory symptoms. We successfully obtained and analyzed samples from 620 (89%) of 700 1-month-old children; a few samples were below the assay detection limit (reported as the median (Inter-Quartile Range (IQR)). The number of samples below the detection limit (i.e.&#160;from 0 to the set point for the lower limit of detection) for each mediator was 29 (7.25 - 119.5). This technique enables the quantification of the in vivo airway mucosal immune profile from birth, can be applied longitudinally, and can be applied to studies on the effect of genetics and early-life environmental exposures, pathophysiology, endotyping, and monitoring of respiratory diseases, and development and evaluation of novel therapeutics.

Baseline Characteristics of the Airway Immune Profiles: 
Complete data on upper airway mucosal immune mediator levels at 1 month of age was obtained in 620 (89%) of the 700 children enrolled in the COPSAC2010 cohort. Ten neonates were enrolled before the technique was established, and 19 did not attend the 1-month visit. Additionally, 47 samples were excluded because they were extracted and measured in another laboratory used in a pilot study, and 4 sample...

Watch this Scientific Journal Video about Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels at JoVE.com

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

This protocol describes a noninvasive technique for the sampling of undisturbed mucosal lining fluid from the upper airways. It can be used to perform the quantification of in vivo levels of protein mediators, such as cytokines and chemokines, in subjects of all ages.

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

This protocol describes noninvasive sampling of undisturbed upper airway mucosal lining fluid. It also details the extraction procedure used prior to the ...

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Unit 1

Upper Respiratory Tract Infections

SCIENTISTS IN ACTION

10.2K vistas.  University of Copenhagen. Este protocolo describe una técnica no invasiva para la toma de muestras del líquido guarnición mucosa de las vías aéreas superiores. Puede ser utilizado para realizar la cuantificación de en vivo los niveles de mediadores de la proteína, tales como citoquinas y quimioquinas, en sujetos de todas las edades.

Video: Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

Mucosal surfaces serve as protective barriers against pathogenic organisms.&#160;Innate immune responses are activated upon sensing pathogen leading to the infiltration of tissues with migrating inflammatory cells, primarily neutrophils.&#160;This process has the potential to be destructive to tissues if excessive or held in an unresolved state.&#160; Cocultured in vitro models can be utilized to study the unique molecular mechanisms involved in pathogen induced neutrophil trans-epithelial migration.&#160;This type of model provides versatility in experimental design with opportunity for controlled manipulation of the pathogen, epithelial barrier, or neutrophil.&#160;Pathogenic infection of the apical surface of polarized epithelial monolayers grown on permeable transwell filters instigates physiologically relevant basolateral to apical trans-epithelial migration of neutrophils applied to the basolateral surface.&#160;The in vitro model described herein demonstrates the multiple steps necessary for demonstrating neutrophil migration across a polarized lung epithelial monolayer that has been infected with pathogenic P. aeruginosa (PAO1).&#160;Seeding and culturing of permeable transwells with human derived lung epithelial cells is described, along with isolation of neutrophils from whole human blood and culturing of PAO1 and nonpathogenic K12 E. coli (MC1000).&#160; The emigrational process and quantitative analysis of successfully migrated neutrophils that have been mobilized in response to pathogenic infection is shown with representative data, including positive and negative controls.&#160;This in vitro model system can be manipulated and applied to other mucosal surfaces.&#160;Inflammatory responses that involve excessive neutrophil infiltration can be destructive to host tissues and can occur in the absence of pathogenic infections.&#160;A better understanding of the molecular mechanisms that promote neutrophil trans-epithelial migration through experimental manipulation of the in vitro coculture assay system described herein has significant potential to identify novel therapeutic targets for a range of mucosal infectious as well as inflammatory diseases.

In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

Neutrophil trans-epithelial migration in response to mucosal bacterial infection contributes to epithelial injury and clinical disease.&#160;An in vitro model has been developed that combines pathogen, human neutrophils, and polarized human epithelial cell layers grown on transwell filters to facilitate investigations towards unraveling the molecular mechanisms orchestrating this phenomenon.

Mucosal surfaces serve as protective barriers against pathogenic organisms.&#160;Innate immune responses are activated upon sensing pathogen leading to ...

Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production

In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. Conversely, viruses have evolved intricate strategies to evade and exploit host immune signaling for survival and propagation. Viral immune evasion, entailing host defense and viral evasion, provides one of the most fascinating and dynamic interfaces to discern the host-virus interaction. These studies advance our understanding in innate immune regulation and pave our way to develop novel antiviral therapies.
Murine &#947;HV68 is a natural pathogen of murine rodents. &#947;HV68 infection of mice provides a tractable small animal model to examine the antiviral response to human KSHV and EBV of which perturbation of in vivo virus-host interactions is not applicable. Here we describe a protocol to determine the antiviral cytokine production. This protocol can be adapted to other viruses and signaling pathways.
Recently, we have discovered that &#947;HV68 hijacks MAVS and IKK&#946;, key innate immune signaling components downstream of the cytosolic RIG-I and MDA5, to abrogate NF&#922;B activation and antiviral cytokine production. Specifically, &#947;HV68 infection activates IKK&#946; and that activated IKK&#946; phosphorylates RelA to accelerate RelA degradation. As such, &#947;HV68 efficiently uncouples NF&#922;B activation from its upstream activated IKK&#946;, negating antiviral cytokine gene expression. This study elucidates an intricate strategy whereby the upstream innate immune activation is intercepted by a viral pathogen to nullify the immediate downstream transcriptional activation and evade antiviral cytokine production.

We describe a protocol to measure the antiviral cytokine production in mice infected with a model herpesvirus, murine gamma herpesvirus 68 (&#947;HV68) that is closely-related to human Kaposi&#8217;s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV). Utilizing genetically modified mouse strains and mouse embryonic fibroblasts (MEFs), we assessed the antiviral cytokine production both in vivo and ex vivo. &#8220;Reconstituting&#8221; the expression of innate immune components in knockout embryonic fibroblasts by lentiviral transduction, we further pinpoint specific innate immune molecules and dissect the key signaling events that differentially regulate the antiviral cytokine production.

In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. ...

Intranasal Administration of Recombinant Influenza Vaccines in Chimeric Mouse Models to Study Mucosal Immunity

Vaccines are one of the greatest achievements of mankind, and have saved millions of lives over the last century. Paradoxically, little is known about the physiological mechanisms that mediate immune responses to vaccines perhaps due to the overall success of vaccination, which has reduced interest into the molecular and physiological mechanisms of vaccine immunity. However, several important human pathogens including influenza virus still pose a challenge for vaccination, and may benefit from immune-based strategies. 
Although influenza reverse genetics has been successfully applied to the generation of live-attenuated influenza vaccines (LAIVs), the addition of molecular tools in vaccine preparations such as tracer components to follow up the kinetics of vaccination in vivo, has not been addressed. In addition, the recent generation of mouse models that allow specific depletion of leukocytes during kinetic studies has opened a window of opportunity to understand the basic immune mechanisms underlying vaccine-elicited protection. Here, we describe how the combination of reverse genetics and chimeric mouse models may help to provide new insights into how vaccines work at physiological and molecular levels, using as example a recombinant, cold-adapted, live-attenuated influenza vaccine (LAIV). We utilized laboratory-generated LAIVs harboring cell tracers as well as competitive bone marrow chimeras (BMCs) to determine the early kinetics of vaccine immunity and the main physiological mechanisms responsible for the initiation of vaccine-specific adaptive immunity. In addition, we show how this technique may facilitate gene function studies in single animals during immune responses to vaccines. We propose that this technique can be applied to improve current prophylactic strategies against pathogens for which urgent medical countermeasures are needed, for example influenza, HIV, Plasmodium, and hemorrhagic fever viruses such as Ebola virus.

There is an overall lack of knowledge about how vaccines work. Here we propose the combined use of reverse genetics and bone marrow chimeric mice to gain insight into the early host immune responses to vaccines with a special focus on dendritic cells and T cell immunity.

Vaccines are one of the greatest achievements of mankind, and have saved millions of lives over the last century. Paradoxically, little is known about the ...

A RAPID Method for Blood Processing to Increase the Yield of Plasma Peptide Levels in Human Blood

Research in the field of food intake regulation is gaining importance. This often includes the measurement of peptides regulating food intake. For the correct determination of a peptide&#39;s concentration, it should be stable during blood processing. However, this is not the case for several peptides which are quickly degraded by endogenous peptidases. Recently, we developed a blood processing method employing Reduced temperatures, Acidification, Protease inhibition, Isotopic exogenous controls and Dilution (RAPID) for the use in rats. Here, we have established this technique for the use in humans and investigated recovery, molecular form and circulating concentration of food intake regulatory hormones. The RAPID method significantly improved the recovery for 125I-labeled somatostatin-28 (+39%), glucagon-like peptide-1 (+35%), acyl ghrelin and glucagon (+32%), insulin and kisspeptin (+29%), nesfatin-1 (+28%), leptin (+21%) and peptide YY3-36 (+19%) compared to standard processing (EDTA blood on ice, p&#160;&#60;0.001). High performance liquid chromatography showed the elution of endogenous acyl ghrelin at the expected position after RAPID processing, while after standard processing 62% of acyl ghrelin were degraded resulting in an earlier peak likely representing desacyl ghrelin. After RAPID processing the acyl/desacyl ghrelin ratio in blood of normal weight subjects was 1:3 compared to 1:23 following standard processing (p&#160;= 0.03). Also endogenous kisspeptin levels were higher after RAPID compared to standard processing (+99%, p&#160;= 0.02). The RAPID blood processing method can be used in humans, yields higher peptide levels and allows for assessment of the correct molecular form.

The RAPID blood processing method can be used in humans and yields higher peptide levels as well as allows for assessment of the correct molecular form. Therefore, this method will be a valuable tool in peptide research.

Research in the field of food intake regulation is gaining importance. This often includes the measurement of peptides regulating food intake. For the ...

Intra-tracheal Administration of Haemophilus influenzae in Mouse Models to Study Airway Inflammation

Here, we describe a detailed procedure to efficiently and directly deliver Haemophilus influenzae into the lower respiratory tracts of mice. We demonstrate the procedure for preparing H. influenzae inoculum, intra-tracheal instillation of H. influenzae into the lung, collection of broncho-alveolar lavage fluid (BALF), analysis of immune cells in the BALF, and RNA isolation for differential gene expression analysis. This procedure can be used to study the lung inflammatory response to any bacteria, virus or fungi. Direct tracheal instillation is mostly preferred over intranasal or aerosol inhalation procedures because it more efficiently delivers the bacterial inoculum into the lower respiratory tract with less ambiguity.

Intra-tracheal Administration of Haemophilus influenzae in Mouse Models to Study Airway Inflammation

We demonstrate the procedure for intra-tracheal inoculation of Haemophilus influenzae into the lower respiratory tracts of mice. This is a very useful tool to study signaling pathways that regulate airway inflammation in mouse models.

Here, we describe a detailed procedure to efficiently and directly deliver Haemophilus influenzae into the lower respiratory tracts of mice. We ...

Swab Sampling Method for the Detection of Human Norovirus on Surfaces

Human noroviruses are a leading cause of epidemic and sporadic gastroenteritis worldwide. Because most infections are either spread directly via the person-to-person route or indirectly through environmental surfaces or food, contaminated fomites and inanimate surfaces are important vehicles for the spread of the virus during norovirus outbreaks.
We developed and evaluated a protocol using macrofoam swabs for the detection and typing of human noroviruses from hard surfaces. Compared with fiber-tipped swabs or antistatic wipes, macrofoam swabs allow virus recovery (range 1.2-33.6%) from toilet seat surfaces of up to 700 cm2. The protocol includes steps for the extraction of the virus from the swabs and further concentration of the viral RNA using spin columns. In total, 127 (58.5%) of 217 swab samples that had been collected from surfaces in cruise ships and long-term care facilities where norovirus gastroenteritis had been reported tested positive for GII norovirus by RT-qPCR. Of these 29 (22.8%) could be successfully genotyped. In conclusion, detection of norovirus on environmental surfaces using the protocol we developed may assist in determining the level of environmental contamination during outbreaks as well as detection of virus when clinical samples are not available; it may also facilitate monitoring of effectiveness of remediation strategies.

A macrofoam based sampling methodology was developed and evaluated for the detection and quantification of norovirus on environmental hard surfaces.

Human noroviruses are a leading cause of epidemic and sporadic gastroenteritis worldwide. Because most infections are either spread directly via the ...

Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification

Biofilm formation is a dynamic, multistage process that occurs in bacteria under harsh environmental conditions or times of stress. For enteric pathogens, a significant stress response is induced during gastrointestinal transit and upon bile exposure, a normal component of human digestion. To overcome the bactericidal effects of bile, many enteric pathogens form a biofilm hypothesized to permit survival when transiting through the small intestine. Here we present methodologies to define biofilm formation through solid-phase adherence assays as well as extracellular polymeric substance (EPS) matrix detection and visualization. Furthermore, biofilm dispersion assessment is presented to mimic the analysis of events triggering release of bacteria during the infection process. Crystal violet staining is used to detect adherent bacteria in a high-throughput 96-well plate adherence assay. EPS production assessment is determined by two assays, namely microscopy staining of the EPS matrix and semi-quantitative analysis with a fluorescently-conjugated polysaccharide binding lectin. Finally, biofilm dispersion is measured through colony counts and plating. Positive data from multiple assays support the characterization of biofilms and can be utilized to identify bile salt-induced biofilm formation in other bacterial strains.

This protocol enables the reader to analyze bile salt-induced biofilm formation in enteric pathogens using a multifaceted approach to capture the dynamic nature of bacterial biofilms by assessing adherence, extracellular polymeric substance matrix formation, and dispersion.

Biofilm formation is a dynamic, multistage process that occurs in bacteria under harsh environmental conditions or times of stress. For enteric pathogens, ...

Quantification of Atherosclerosis in Mice

Cardiovascular disease is the main cause of death in the world. The underlying cause in most cases is atherosclerosis, which is in part a chronic inflammatory disease. Experimental atherosclerosis studies have elucidated the role of cholesterol and inflammation in the disease process. This has led to successful clinical trials with pharmaceutical agents that reduce clinical manifestations of atherosclerosis. Careful and well-controlled experiments in mouse models of the disease could further elucidate the pathogenesis of the disease, which is not fully understood. Standardized lesion analysis is important to reduce experimental variability and increase reproducibility. Determining lesion size in aortic root, aortic arch, and brachiocephalic artery are common endpoints in experimental atherosclerosis. This protocol provides a technical description for evaluation of atherosclerosis at all these sites in a single mouse. The protocol is particularly useful when material is limited, as is frequently the case when genetically modified animals are being characterized.

Murine models of atherosclerosis are useful tools to investigate pathogenic pathways on a molecular level, but require standardized quantification of lesion development. This protocol describes an optimized method to determine lesion size in the major arterial vessels including the aortic root, aortic arch, and brachiocephalic artery.

Cardiovascular disease is the main cause of death in the world. The underlying cause in most cases is atherosclerosis, which is in part a chronic ...

Isolation of Tonsillar Mononuclear Cells to Study Ex Vivo Innate Immune Responses in a Human Mucosal Lymphoid Tissue

Studying isolated cells from mucosa-associated lymphoid tissues (MALT) allows understanding of immune cells response in pathologies involving mucosal immunity, because they can model host-pathogen interactions in the tissue. While isolated cells derived from tissues were the first cell culture model, their use has been neglected because tissue can be hard to obtain. In the present protocol, we explain how to easily process and culture tonsillar mononuclear cells (TMCs) from healthy human tonsils to study innate immune responses upon activation, mimicking viral infection in mucosal tissues. Isolation of TMCs from the tonsils is quick, because the tonsils barely have any epithelium and yield up to billions of all major immune cell types. This method allows detection of cytokine production using several techniques, including immunoassays, qPCR, microscopy, flow cytometry, etc., similar to the use of peripheral mononuclear cells (PBMCs) from blood. Furthermore, TMCs show a higher sensitivity to drug testing than PBMCs, which needs to be considered for future toxicity assays. Thus, ex vivo TMCs cultures are an easy and accessible mucosal model.

In the present protocol, we explain how to easily process and culture tonsillar mononuclear cells from healthy humans undergoing partial surgical tonsillectomy to study innate immune responses upon activation, mimicking viral infection in mucosal tissues.

Studying isolated cells from mucosa-associated lymphoid tissues (MALT) allows understanding of immune cells response in pathologies involving mucosal ...

Production of Monoclonal Antibodies Targeting Aminopeptidase N in the Porcine Intestinal Mucosal Epithelium

Porcine aminopeptidase N (APN), a membrane-bound metallopeptidase abundantly present in small intestinal mucosa, can initiate a mucosal immune response without any interference such as low protein expression, enzyme inactivity, or structural changes. This makes APN an attractive candidate in the development of vaccines that selectively target the mucosal epithelium. Previous studies have shown that APN is a receptor protein for both enterotoxigenic Escherichia coli (E. coli) F4 and transmissible gastroenteritis virus. Thus, APN shows promise in the development of antibody-drug conjugates or novel vaccines based on APN-specific antibodies. In this study, we compared production of APN-specific monoclonal antibodies (mAbs) using traditional hybridoma technology and recombinant antibody expression method. We also established a stably transfected Chinese hamster ovary (CHO) cell line using pIRES2-ZSGreen1-rAbs-APN and an E. coli expression BL21(DE3) strain harboring the pET28a (+)-rAbs-APN vector. The results show that antibodies expressed in pIRES2-ZSGreen1-rAbs-APN-CHO cells and mAbs produced using hybridomas could recognize and bind to the APN protein. This provides the basis for further elucidation of the APN receptor function for the development of therapeutics targeting different APN-specific epitopes.

The recombinant antibody protein expressed in pIRES2-ZSGreen1-rAbs-APN-CHO cells and monoclonal antibodies produced using traditional hybridoma technology can recognize and bind to the porcine aminopeptidase N (APN) protein.

Porcine aminopeptidase N (APN), a membrane-bound metallopeptidase abundantly present in small intestinal mucosa, can initiate a mucosal immune response ...