The authors would like to thank other members of the Tigno-Aranjuez Lab including Madelyn H. Miller, Omar Cardona, Andjie Jeudy, and Roopin Singh for their help in laboratory upkeep and mouse colony maintenance. Support for this research was provided by grant R00 HL122365 and Start-up funds to J.T.T-A.

<ol>
	<li>Winterbourn, C. C., Kettle, A. J., Hampton, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactive+Oxygen+Species+and+Neutrophil+Function.">Reactive Oxygen Species and Neutrophil Function.</a> Annual Review of Biochemistry. 85, 765-792 (2016).</li><li>Schieber, M., Chandel, N. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ROS+function+in+redox+signaling+and+oxidative+stress.">ROS function in redox signaling and oxidative stress.</a> Current Biology. 24 (10), R453-R462 (2014).</li><li>Robinson, J. 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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=Fatal+(chronic)+granulomatous+disease+of+childhood:+a+hereditary+defect+of+leukocyte+function.">Fatal (chronic) granulomatous disease of childhood: a hereditary defect of leukocyte function.</a> Seminars in Hematology. 5 (3), 215-254 (1968).</li><li>Holmes, B., Page, A. R., Good, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+of+the+metabolic+activity+of+leukocytes+from+patients+with+a+genetic+abnormality+of+phagocytic+function.">Studies of the metabolic activity of leukocytes from patients with a genetic abnormality of phagocytic function.</a> Journal of Clinical Investigation. 46 (9), 1422-1432 (1967).</li><li>Windhorst, D. B., Page, A. R., Holmes, B., Quie, P. G., Good, R. 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The authors have no conflicts of interest to disclose.

DCFH2-DA and DHE-based detection of ROS is a widely-used technique14,15. Ease of use and the adaptability of these ROS probes for kinetic microplate formats, fluorescence microscopy or flow cytometric analysis has contributed to their popularity. However, in our studies of Fc&#947;R-mediated macrophage functions, there did not seem to be a standard protocol for performing this assay for flow cytometric analysis of Fc&#947;R cross-linked cells. Given th...

Reactive oxygen species (ROS) are reactive molecules or free radicals that are by-products of aerobic respiration (reviewed in 1). These include the superoxide anion, peroxide, hydrogen peroxide, hydroxyl radical, and hydroxyl ions, among others. Under normal physiologic conditions, ROS are produced mainly by the mitochondria and nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and are rapidly detoxified by various enzymes and proteins such as superoxide dismutase and glutathione. An exaggerated production of ROS or a defect in the ability to remove ROS can result in oxidative stress, whereby reactive oxygen species promote the damage of proteins, lipids, and DNA leading to cellular stress or death and pathological disease states. However, it is currently appreciated that ROS can also act as signaling molecules (redox signaling), and ROS-mediated modification of various molecules and pathway intermediates can influence cellular metabolism, proliferation, survival, inflammatory signaling, and aging2. In phagocytic cells, ROS plays an essential role in providing antimicrobial activity during the so-called &#8220;respiratory burst&#8221;1,3,4,5,6. During the response of phagocytes to external stimuli, components of the NADPH oxidase complex (p40phox, p47phox, p67phox) translocate from the cytosol to the phagosomal membrane containing the gp91phox and p22phox subunits, and together with the actions of Rac1/2, form a fully functional NADPH oxidase enzyme complex. The assembled NADPH oxidase then utilizes NADPH to reduce oxygen to superoxide within the phagosomal vacuole. Superoxide anions can directly cause damage or be dismutated into hydrogen peroxide. Both superoxide and hydrogen peroxide can react with other molecules to generate highly reactive hydroxyl radicals. Damage is mediated by reaction of these ROS with iron-sulfur clusters on proteins or by causing base oxidation of DNA, ultimately leading to restricted microbial metabolism or death of the microbe5. The importance of the NADPH oxidase enzyme complex and ROS produced during the respiratory burst is illustrated clinically in patients with Chronic Granulomatous Disease (CGD)7,8,9,10. Individuals with CGD possess mutations in gp91phox, resulting in a lack of ROS production and susceptibility to recurrent infections with bacteria and fungi which are not usually a concern with immunocompetent individuals. Therefore, whether studying oxidative stress, redox signaling, or host defense, being able to measure ROS production in real-time is a useful endeavor.
Multiple assays have been utilized to measure ROS production or the results of oxidative stress11,12,13. Among these, one of the most widely used is the fluorescent probe 2&#8217;,7&#8217; dichlorodihydrofluorescein diacetate (DCFH2-DA)14. This molecule is colorless and lipophilic. Diffusion of DCFH2-DA across the cell membrane allows it to be acted upon by intracellular esterases, which deacetylates it into DCFH2, rendering it cell impermeable. The actions of multiple types of ROS (hydrogen peroxide, peroxynitrite, hydroxyl radicals, nitric oxide, and peroxy radicals) on DCFH2 oxidize it into DCF which is fluorescent (reported Ex/Em: 485-500 nm/515-530 nm) and can be detected using a flow cytometer equipped with a standard filter set for fluorescein (FL1 channel). Superoxide does not strongly react with DCFH2 but can react with another probe dihydroethidium (DHE) to yield the fluorescent product 2-hydroxyethidium (as well as other fluorescent superoxide-independent oxidation products)15. The fluorescent products of DHE oxidation can be detected using an excitation wavelength of 518 nm and an emission wavelength of 605 nm (FL2 channel). Although relatively simple to use, utilization of these probes for detection of ROS requires knowledge of their limitations and careful incorporation of staining procedures and controls into the specific assay being performed in order to have valid experimental results and conclusions. The following protocol demonstrates the use of a commercially available kit employing these 2 probes designed to measure ROS by flow cytometry. We stain primed bone marrow-derived macrophages with these probes and induce ROS production through Fc&#947;R cross-linking. We present representative data obtained using this protocol and stress appropriate precautions that must be undertaken for successful experimentation.

<table border="0" cellpadding="0" cellspacing="0" style="width:623px;" width="623">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Anti-BSA IgG1</td>
			<td style="width:121px;">Innovative Research</td>
			<td style="width:119px;">IBSA9E2C2</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Alexa Fluor 647 Rat IgG2b, &#954; Isotype Ctrl Antibody</td>
			<td style="width:121px;">BioLegend</td>
			<td style="width:119px;">400626</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Anti-mouse CD16/32</td>
			<td style="width:121px;">BioLegend</td>
			<td style="width:119px;">101302</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Anti-mouse F4/80 antibody conjugated to Alexa Fluor 647</td>
			<td style="width:121px;">BD Biosciences</td>
			<td style="width:119px;">565853</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Anti-mouse F4/80 antibody conjugated to FITC</td>
			<td style="width:121px;">BioLegend</td>
			<td style="width:119px;">123108</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Anti-mouse/human CD11b antibodyconjugated to Alexa Fluor 647&#160;</td>
			<td style="width:121px;">BioLegend</td>
			<td style="width:119px;">101218</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">beta-mercaptoethanol (BME)</td>
			<td style="width:121px;">Sigma</td>
			<td style="width:119px;">M3148-100ml</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Bovine Serum Albumin (BSA) FractionV</td>
			<td style="width:121px;">Fisher</td>
			<td style="width:119px;">BP1600-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">C57BL/6J&#160;</td>
			<td style="width:121px;">Jackson labs</td>
			<td>Stock No.000664</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">CM-H2DCFDA</td>
			<td style="width:121px;">Molecular Probes</td>
			<td style="width:119px;">C6827</td>
			<td>Can be a substitute for oxidative stress detection reagent in the Enzo kit</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dihydroethidium (DHE)</td>
			<td style="width:121px;">Molecular Probes</td>
			<td style="width:119px;">D11347</td>
			<td>Can be a substitute for superoxide detection reagent in the Enzo kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DMEM 1x</td>
			<td style="width:121px;">Corning</td>
			<td style="width:119px;">10-013-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DMEM no phenol red</td>
			<td style="width:121px;">Gibco</td>
			<td style="width:119px;">31053-028</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DMF Anhydrous&#160;</td>
			<td style="width:121px;">Acros Organics</td>
			<td style="width:119px;">61094-1000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:121px;">VWR</td>
			<td style="width:119px;">97068-085</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">FITC Rat IgG2a, &#954; Isotype Ctrl Antibody</td>
			<td style="width:121px;">BioLegend</td>
			<td style="width:119px;">400506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">HEPES (1M)</td>
			<td style="width:121px;">Gibco</td>
			<td style="width:119px;">15630-080</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">L glutamine</td>
			<td style="width:121px;">Gibco</td>
			<td style="width:119px;">25030-081</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">LADMAC cells</td>
			<td style="width:121px;">ATCC</td>
			<td>CRL-2420</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MEM</td>
			<td style="width:121px;">Corning</td>
			<td style="width:119px;">10-010-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">mouse IFN-g</td>
			<td style="width:121px;">GoldBio</td>
			<td style="width:119px;">1360-06-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">N-Acetyl-L-cysteine</td>
			<td style="width:121px;">EMD Milipore</td>
			<td style="width:119px;">106425</td>
			<td>Can be a substitute for ROS inhibitor/scavenger in the Enzo kit</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Novocyte flow cytometer with autosampler</td>
			<td style="width:121px;">Acea</td>
			<td style="width:119px;">2060R</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Pyocyanin (ROS inducer)</td>
			<td style="width:121px;">Cayman chemical</td>
			<td style="width:119px;">10009594</td>
			<td>Can be a substitute for inducer in the Enzo kit</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">ROS-ID total ROS/superoxide detection kit</td>
			<td style="width:121px;">ENZO</td>
			<td style="width:119px;">ENZ-51010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sodium pyruvate (100mM)</td>
			<td style="width:121px;">Gibco</td>
			<td style="width:119px;">11360-070</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Trypsin-EDTA (0.25%)</td>
			<td style="width:121px;">Gibco</td>
			<td style="width:119px;">25200-056</td>
			<td></td>
		</tr>
	</tbody>
</table>

flow cytometric measurement of ros production in macrophages in response to fc&#947;r cross-linking

The oxidative or respiratory burst is used to describe the rapid consumption of oxygen and generation of reactive oxygen species (ROS) by phagocytes in response to various immune stimuli. ROS generated during immune activation exerts potent antimicrobial activity primarily through the ability of ROS to damage DNA and proteins, causing death of microorganisms. Being able to measure ROS production reproducibly and with ease is necessary in order to assess the contribution of various pathways and molecules to this mechanism of host defense. In this paper, we demonstrate the use of fluorescent probes and flow cytometry to detect ROS production. Although widely used, fluorescent measurement of ROS is notoriously problematic, especially with regards to measurement of ROS induced by specific and not mitogenic stimuli. We present a detailed methodology to detect ROS generated as a result of specific Fc&#947;R stimulation beginning with macrophage generation, priming, staining, Fc&#947;R cross-linking, and ending with flow cytometric analysis.

Using the protocol outlined within, we present representative data demonstrating flow cytometric detection of ROS production resulting from stimulation of WT C57BL/6J BMDMs through the Fc&#947;R. As expected, we observe minimal changes in FL1 or FL2 fluorescence above background levels in unstimulated cells (Figure 3A, compare &#8220;stained, unstimulated&#8221; vs &#8220;unstained, unstimulated&#8221; dot plots). We observe a marked increase in FL1 and FL2 fluorescence when cells are stimul...

Watch this Scientific Journal Video about Flow Cytometric Measurement Of ROS Production In Macrophages In Response To FcÃŽÂ³R Cross-linking at JoVE.com

Flow Cytometric Measurement Of ROS Production In Macrophages In Response To Fc&#947;R Cross-linking

This study demonstrates the use of flow cytometry to detect reactive oxygen species (ROS) production resulting from activation of the Fc&#947;R. This method can be used to assess changes in the antimicrobial and redox signaling function of phagocytes in response to immune complexes, opsonized microorganisms, or direct Fc&#947;R cross-linking.

The oxidative or respiratory burst is used to describe the rapid consumption of oxygen and generation of reactive oxygen species (ROS) by phagocytes in ...

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Research

JoVE Journal

Immunology and Infection

15.5K Views.  University of Central Florida. This study demonstrates the use of flow cytometry to detect reactive oxygen species (ROS) production resulting from activation of the FcγR. This method can be used to assess changes in the antimicrobial and redox signaling function of phagocytes in response to immune complexes, opsonized microorganisms, or direct FcγR cross-linking.

Video: Flow Cytometric Measurement Of ROS Production In Macrophages In Response To FcγR Cross-linking

Multicolor Flow Cytometry Analyses of Cellular Immune Response in Rhesus Macaques

The rhesus macaque model is currently the best available model for HIV-AIDS with respect to understanding the pathogenesis as well as for the development of vaccines and therapeutics1,2,3. Here, we describe a method for the detailed phenotypic and functional analyses of cellular immune responses, specifically intracellular cytokine production by CD4+ and CD8+ T cells as well as the individual memory subsets. We obtained precise quantitative and qualitative measures for the production of interferon gamma (INF-) and interleukin (IL) -2 in both CD4+ and CD8+ T cells from the rhesus macaque PBMC stimulated with PMA plus ionomycin (PMA+I). The cytokine profiles were different in the different subsets of memory cells. Furthermore, this protocol provided us the sensitivity to demonstrate even minor fractions of antigen specific CD4+ and CD8+ T cell subsets within the PBMC samples from rhesus macaques immunized with an HIV envelope peptide cocktail vaccine developed in our laboratory. The multicolor flow cytometry technique is a powerful tool to precisely identify different populations of T cells 4,5 with cytokine-producing capability6 following non-specific or antigen-specific stimulation 5,7.

We demonstrate the utility of multicolor flow cytometry for detailed phenotypic and functional characterization of total as well as memory subsets of CD4+ and CD8+ T cells in rhesus macaques, the ideal model for HIV/AIDS vaccine studies.

The rhesus macaque model is currently the best available model for HIV-AIDS with respect to understanding the pathogenesis as well as for the development ...

Quantitative Measurement of the Immune Response and Sleep in Drosophila

A complex interaction between the immune response and host behavior has been described in a wide range of species. Excess sleep, in particular, is known to occur as a response to infection in mammals 1 and has also recently been described in Drosophila melanogaster2. It is generally accepted that sleep is beneficial to the host during an infection and that it is important for the maintenance of a robust immune system3,4. However, experimental evidence that supports this hypothesis is limited4, and the function of excess sleep during an immune response remains unclear. We have used a multidisciplinary approach to address this complex problem, and have conducted studies in the simple genetic model system, the fruitfly Drosophila melanogaster. We use a standard assay for measuring locomotor behavior and sleep in flies, and demonstrate how this assay is used to measure behavior in flies infected with a pathogenic strain of bacteria. This assay is also useful for monitoring the duration of survival in individual flies during an infection. Additional measures of immune function include the ability of flies to clear an infection and the activation of NF&kappa;B, a key transcription factor that is central to the innate immune response in Drosophila. Both survival outcome and bacterial clearance during infection together are indicators of resistance and tolerance to infection. Resistance refers to the ability of flies to clear an infection, while tolerance is defined as the ability of the host to limit damage from an infection and thereby survive despite high levels of pathogen within the system5. Real-time monitoring of NF&kappa;B activity during infection provides insight into a molecular mechanism of survival during infection. The use of Drosophila in these straightforward assays facilitates the genetic and molecular analyses of sleep and the immune response and how these two complex systems are reciprocally influenced.

Quantitative Measurement of the Immune Response and Sleep in Drosophila

To understand a link between the immune response and behavior, we describe a method to measure locomotor behavior in Drosophila during bacterial infection as well as the ability of flies to mount an immune response by monitoring survival, bacterial load, and real-time activity of a key regulator of innate immunity, NF&kappa;B.

A complex interaction between the immune response and  host behavior has been described in a wide range of species. Excess sleep, in  particular, is known ...

Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs

Mimicking and exploiting virus properties and physicochemical and physical characteristics holds promise to provide solutions to some of the world's most pressing challenges. The sheer range and types of viruses coupled with their intriguing properties potentially give endless opportunities for applications in virus-based technologies. Viruses have the ability to self- assemble into particles with discrete shape and size, specificity of symmetry, polyvalence, and stable properties under a wide range of temperature and pH conditions. Not surprisingly, with such a remarkable range of properties, viruses are proposed for use in biomaterials 9, vaccines 14, 15, electronic materials, chemical tools, and molecular electronic containers4, 5, 10, 11, 16, 18, 12.
In order to utilize viruses in nanotechnology, they must be modified from their natural forms to impart new functions. This challenging process can be performed through several mechanisms including genetic modification of the viral genome and chemically attaching foreign or desired molecules to the virus particle reactive groups 8. The ability to modify a virus primarily depends upon the physiochemical and physical properties of the virus. In addition, the genetic or physiochemical modifications need to be performed without adversely affecting the virus native structure and virus function. Maize rayado fino virus (MRFV) coat proteins self-assemble in Escherichia coli producing stable and empty VLPs that are stabilized by protein-protein interactions and that can be used in virus-based technologies applications 8. VLPs produced in tobacco plants were examined as a scaffold on which a variety of peptides can be covalently displayed 13. Here, we describe the steps to 1) determine which of the solvent-accessible cysteines in a virus capsid are available for modification, and 2) bioconjugate peptides to the modified capsids. By using native or mutationally-inserted amino acid residues and standard coupling technologies, a wide variety of materials have been displayed on the surface of plant viruses such as, Brome mosaic virus 3, Carnation mottle virus 12, Cowpea chlorotic mottle virus 6, Tobacco mosaic virus 17, Turnip yellow mosaic virus 1, and MRFV 13.

Analysis of the Solvent Accessibility of Cysteine Residues on Maize rayado fino virus Virus-like Particles Produced in Nicotiana benthamiana Plants and Cross-linking of Peptides to VLPs

A method to analyze the solvent accessibility of the thiol group of cysteine residues of Maize rayado fino virus (MRFV)-virus-like particles (VLPs) followed by a peptide cross-linking reaction is described. The method takes advantage of the availability of several chemical groups on the surface of the VLPs that can be targets for specific reactions.

Mimicking  and exploiting virus properties and physicochemical and physical  characteristics holds promise to provide solutions to some of  the world's ...

Using RNA-interference to Investigate the Innate Immune Response in Mouse Macrophages

Macrophages are key phagocytic innate immune cells. When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the pathogen, produce various cytokines and chemokines to recruit and stimulate other immune cells, and present antigens to stimulate the adaptive immune response. Thus, being able to efficiently manipulate macrophages with techniques such as RNA-interference (RNAi) is critical to our ability to investigate this important innate immune cell. However, macrophages can be technically challenging to transfect and can exhibit inefficient RNAi-induced gene knockdown. In this protocol, we describe methods to efficiently transfect two mouse macrophage cell lines (RAW264.7 and J774A.1) with siRNA using the Amaxa Nucleofector 96-well Shuttle System and describe procedures to maximize the effect of siRNA on gene knockdown. Moreover, the described methods are adapted to work in 96-well format, allowing for medium and high-throughput studies. To demonstrate the utility of this approach, we describe experiments that utilize RNAi to inhibit genes that regulate lipopolysaccharide (LPS)-induced cytokine production.

In this protocol, we describe methods to efficiently transfect murine macrophage cell lines with siRNAs using the Amaxa Nucleofector 96-well Shuttle System, stimulate the macrophages with lipopolysaccharide, and monitor the effects on inflammatory cytokine production.

Macrophages are key phagocytic innate immune cells.  When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the ...

A Simple Flow Cytometric Method to Measure Glucose Uptake and Glucose Transporter Expression for Monocyte Subpopulations in Whole Blood

Monocytes are innate immune cells that can be activated by pathogens and inflammation associated with certain chronic inflammatory diseases. Activation of monocytes induces effector functions and a concomitant shift from oxidative to glycolytic metabolism that is accompanied by increased glucose transporter expression. This increased glycolytic metabolism is also observed for trained immunity of monocytes, a form of innate immunological memory. Although in vitro protocols examining glucose transporter expression and glucose uptake by monocytes have been described, none have been examined by multi-parametric flow cytometry in whole blood. We describe a multi-parametric flow cytometric protocol for the measurement of fluorescent glucose analog 2-NBDG uptake in whole blood by total monocytes and the classical (CD14++CD16-), intermediate (CD14++CD16+) and non-classical (CD14+CD16++) monocyte subpopulations. This method can be used to examine glucose transporter expression and glucose uptake for total monocytes and monocyte subpopulations during homeostasis and inflammatory disease, and can be easily modified to examine glucose uptake for other leukocytes and leukocyte subpopulations within blood.

Monocytes are integral components of the human innate immune system that rely on glycolytic metabolism when activated. We describe a flow cytometry protocol to measure glucose transporter expression and glucose uptake by total monocytes and monocyte subpopulations in fresh whole blood.

Monocytes are innate immune cells that can be activated by pathogens and inflammation associated with certain chronic inflammatory diseases. Activation of ...

Flow Cytometric Analysis of Particle-bound Bet v 1 Allergen in PM10

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in diameter. In addition to a characterization of forward and sideward scatter properties, it enables the use of fluorescent labeled markers like antibodies to detect respective structures. Using indirect antibody staining, flow cytometry is employed here to quantify birch pollen allergen (precisely Bet v 1)-loaded particles of 0.5 to 10 &#181;m in diameter in inhalable particulate matter (PM10, particle size &#8804;10 &#181;m in diameter). PM10 particles may act as carriers of adsorbed allergens possibly transporting them to the lower respiratory tract, where they could trigger allergic reactions.
So far the allergen content of PM10 has been studied by means of enzyme linked immunosorbent assays (ELISAs) and scanning electron microscopy. ELISA measures the dissolved and not the particle-bound allergen. Compared to scanning electron microscopy, which can visualize allergen-loaded particles, flow cytometry may additionally quantify them. As allergen content of ambient air can deviate from birch pollen count, allergic symptoms might perhaps correlate better with allergen exposure than with pollen count. In conjunction with clinical data, the presented method offers the opportunity to test in future experiments whether allergic reactions to birch pollen antigens are associated with the Bet v 1 allergen content of PM10 particles &#62;0.5 &#181;m.

Here, we present a protocol to quantify allergen-loaded particles by flow cytometry. Ambient particulate matter particles may act as carriers of adsorbed allergens. We show here that flow cytometry, a method widely used to characterize suspended solids &#62;0.5 &#181;m in diameter, can be used to measure these allergen-loaded particles.

Flow cytometry is a method widely used to quantify suspended solids such as cells or bacteria in a size range from 0.5 to several tens of micrometers in ...

Flow Cytometric Analysis of Natural Killer Cell Lytic Activity in Human Whole Blood

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and reproducibility of this assay can be considered unstable, either because of user&#39;s errors or because of the sensitivity of NK cells to experimental manipulation. To eliminate these issues, a workflow that reduces them to a minimum was established and is presented here. To illustrate, we obtained blood samples, at various time points, from runners (n = 4) that were submitted to an intense bout of exercise. First, NK cells are simultaneously identified and isolated through CD56 tagging and magnetic-based sorting, directly from whole blood and from as little as one milliliter. The sorted NK cells are removed of any reagent or capping antibodies. They can be counted in order to establish an accurate NK cell count per milliliter of blood. Secondly, the sorted NK cells (effectors cells or E) can be mixed with 3,3&#39;-Diotadecyloxacarbocyanine Perchlorate (DiO) tagged K562 cells (target cells or T) at an assay-optimal 1:5 T:E ratio, and analyzed using an imaging flow-cytometer that allows for the visualization of each event and the elimination of any false positive or false negatives (such as doublets or effector cells). This workflow can be completed in about 4 h, and allows for very stable results even when working with human samples. When available, research teams can test several experimental interventions in human subjects, and compare measurements across several time points without compromising the data&#39;s integrity.

This work describes an advanced workflow for the accurate and fast determination of NK (Natural Killer) cell count and NK cell cytotoxicity in human blood samples.

NK cell cytotoxicity is a widely used measure to determine the effect of outside intervention on NK cell function. However, the accuracy and ...

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. typhimurium bacteria are quickly detected and phagocytized by macrophages, and contained in vesicles known as phagosomes in order to be degraded. Isolation of S. typhimurium-containing phagosomes have been widely used to study how S. typhimurium infection alters the process of phagosome maturation to prevent bacterial degradation. Classically, the isolation of bacteria-containing phagosomes has been performed by sucrose gradient centrifugation. However, this process is time-consuming, and requires specialized equipment and a certain degree of dexterity. Described here is a simple and quick method for the isolation of S. typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin-streptavidin-conjugated magnetic beads. Phagosomes obtained by this method can be suspended in any buffer of choice, allowing the utilization of isolated phagosomes for a broad range of assays, such as protein, metabolite, and lipid analysis. In summary, this method for the isolation of S. typhimurium-containing phagosomes is specific, efficient, rapid, requires minimum equipment, and is more versatile than the classical method of isolation by sucrose gradient-ultracentrifugation.

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

We describe here a simple and quick method for the isolation of Salmonella typhimurium-containing phagosomes from macrophages by coating the bacteria with biotin and streptavidin.

Salmonella typhimurium is a facultative intracellular bacterium that causes gastroenteritis in humans. After invasion of the lamina propria, S. ...

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and their important role in lung development and function, as well as their lung-localized responses to infection and inflammation. To date, no unified method for identification, isolation, and handling of alveolar macrophages from humans and mice exists. Such a method is needed for studies on these important innate immune cells in various experimental settings. The method described here, which can be easily adopted by any laboratory, is a simplified approach to harvesting alveolar macrophages from bronchoalveolar lavage fluid or from lung tissue and maintaining them in vitro. Because alveolar macrophages primarily occur as adherent cells in the alveoli, the focus of this method is on dislodging them prior to harvest and identification. The lung is a highly vascularized organ, and various cell types of myeloid and lymphoid origin inhabit, interact, and are influenced by the lung microenvironment. By using the set of surface markers described here, researchers can easily and unambiguously distinguish alveolar macrophages from other leukocytes, and purify them for downstream applications. The culture method developed herein supports both human and mouse alveolar macrophages for in vitro growth, and is compatible with cellular and molecular studies.

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

This communication describes methodologies for isolation and culture of alveolar macrophages from humans and murine models for experimental purposes.

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and ...

Flow Cytometric Characterization of Murine B Cell Development

Extensive studies have characterized the development and differentiation of murine B cells in secondary lymphoid organs. Antibodies secreted by B cells have been isolated and developed into well-established therapeutics. Validation of murine B cell development, in the context of autoimmune prone mice, or in mice with modified immune systems, is a crucial component of developing or testing therapeutic agents in mice and is an appropriate use of flow cytometry. Well established B cell flow cytometric parameters can be used to evaluate B cell development in the murine peritoneum, bone marrow, and spleen, but a number of best practices must be adhered to. In addition, flow cytometric analysis of B cell compartments should also complement additional readouts of B cell development. Data generated using this technique can further our understanding of wild type, autoimmune prone mouse models as well as humanized mice that can be used to generate antibody or antibody-like molecules as therapeutics.

We describe herein a simple analysis of the heterogeneity of the murine immune B cell compartment in the peritoneum, spleen, and bone marrow tissues by flow cytometry. The protocol can be adapted and extended to other mouse tissues.

Extensive studies have characterized the development and differentiation of murine B cells in secondary lymphoid organs. Antibodies secreted by B cells ...