Name: stability and structure of bat major histocompatibility complex class i with heterologous &beta;2-microglobulin
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This study was supported by the open fund of state key laboratory of Pharmaceutical Biotechnology, Nan-jing University, China (Grant no. KF-GN-201905), the National Natural Science Foundation of China (grants 81971501). William J. Liu is supported by the Excellent Young Scientist Program of the NSFC (81822040) and Beijing New-star Plan of Science and Technology (Z181100006218080).

1. Preparation of expression constructs
<ol>
	<li>Retrieve the sequences of MHC class I genes (including predicted genes) from bats from the NCBI database.</li>
	<li>Retrieve higher mammal MHC I heavy chain sequences from the Immuno Polymorphism Database (IPD) (www.ebi.ac.uk/ipd/mhc) and the UniProt database (www.uniprot.org).</li>
	<li>To obtain soluble MHC complexes, mutagenize the sequences to remove the cytosolic and transmembrane regions.</li>
	<li>Clone the genes encoding the ectodomains of the bat Ptal-N*01:01 (...

<ol>
	<li>Vyas, J. M., Van der Veen, A. G., Ploegh, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+known+unknowns+of+antigen+processing+and+presentation.">The known unknowns of antigen processing and presentation.</a> Nature Reviews Immunology. 8 (8), 607-618 (2008).</li><li>Bjorkman, P. J., 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=Structure+of+the+human+class+I+histocompatibility+antigen,+HLA-A2.">Structure of the human class I histocompatibility antigen, HLA-A2.</a> Nature. 329 (6139), 506-512 (1987).</li><li>Seong, R. H., Clayberger, C. A., Krensky, A. M., Parnes, J. 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The construction of a hybrid protein complex through heterologous substitution from different taxa is a common strategy for functional and structural investigations when the homologous complex is not available, such as in the MHC I and its ligands. However, there is limited summarization regarding the methodology and the technology. Herein, the structure of bat MHC I, Ptal-N*01:01, stabilized by b&#946;2m or h&#946;2m was analyzed. The key amino acids of &#946;2m binding to Ptal-N*01:01 w...

The major histocompatibility complex (MHC) exists in all vertebrates and is a set of genes that determines the cell-mediated immunity to infectious pathogens. MHC class I presents endogenous peptides, such as viral components produced upon virus infection, to T cell receptors (TCR) on the surface of CD8+ T cells to mediate cellular immunity and participate in immune regulation1. A structural study of MHC I binding to peptides provides information regarding peptide binding motifs and presentation features by MHC I molecules, which plays vital roles in evaluation of CD8+ T cell immune responses and vaccine development.
Since the first crystallization and structural determination of MHC I molecular by Bjorkman et al.2, the crystal structure analysis of MHC I molecules has greatly promoted the understanding of how peptides bind to MHC I molecules, and helps to understand the interaction of light chains with heavy chains and peptides. A series of follow-up studies indicated that although the genes encoding the light chain is not associated with the MHC, the light chain is a key protein for the assembly of MHC I molecules3,4. It interacts with the three domains of MHC class I molecules on multiple surfaces. When the light chain is absent, MHC class I molecules cannot be correctly expressed on the surface of antigen-presenting cells and cannot interact with TCR to exert their immunological functions.
MHC I is comprised of a heavy chain (H chain) and light chain (i.e., &#946;2-microglobulin (&#946;2m)), and is assembled through binding to a suitable peptide5. The extracellular segment of the H chain consists of &#945;1, &#945;2 and &#945;3 domains6. The &#945;1 and &#945;2 domains form the peptide binding groove (PBG). The &#946;2m chain acts as a structural subunit of the assembly complex in MHC I, stabilizing the conformation of the complex, and is a molecular chaperone for MHC I H chain folding7,8,9. A series of studies have shown that MHC I H chains from various mammals such as bat (Chiroptera) (Ptal-N*01:01)10, rhesus macaque (Primates) (Mamu-B*17)11 (Mamu-A*01)12 (Mamu-A*02)13, mouse (Rodentia) (H-2Kd)14,15, dog (Carnivora) (DLA-88*50801)16, cattle (Artiodactyla) (BoLA-A11)17 and equine (Perissodactyla) (Eqca-N*00602 and Eqca-N*00601)18 can combine with heterologous &#946;2m (Table 1). These hybrid molecules are often used in structural and functional studies. However, the methodology for the functional and structural study of the hybrid MHC I with heterologous &#946;2m is not yet summarized. Meanwhile, the structural basis for the interchanged &#946;2m between different taxa remain unclear.
Herein, the procedure for MHC I expression, refolding, crystallization, crystal data collection and structure determination are summarized. In addition, potential substitutions of &#946;2m from different species are analyzed through comparing the structural conformation of MHC I stabilized by homologous and heterologous &#946;2m. These methods will be helpful for further MHC I structural study and CD8+ T cell immune response evaluation in cancer and infectious disease.

<table>
	<tbody>
		<tr>
			<td>10 kDa MMCO membrane</td>
			<td>Merck millipore</td>
			<td>PLGC07610</td>
			<td></td>
		</tr>
		<tr>
			<td>30% Acrylamide</td>
			<td>LABLEAD</td>
			<td>A3291-500ml*5</td>
			<td></td>
		</tr>
		<tr>
			<td>5&#215;Protein SDS Loading</td>
			<td>Novoprotein</td>
			<td>PM099-01A</td>
			<td></td>
		</tr>
		<tr>
			<td>AMICON ULTRA-15 15ML-10 KDa cutoff</td>
			<td>Merck millipore</td>
			<td>UFC901096</td>
			<td></td>
		</tr>
		<tr>
			<td>Ampicillin</td>
			<td>Inalco</td>
			<td>1758-9314</td>
			<td></td>
		</tr>
		<tr>
			<td>APS</td>
			<td>Sigma</td>
			<td>A3678-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>BL21(DE3) strain</td>
			<td>TIANGEN</td>
			<td>CB105-02</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>MP</td>
			<td>219605580</td>
			<td>Wear suitable gloves and eye/face protection. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.</td>
		</tr>
		<tr>
			<td>DTT</td>
			<td>Solarbio</td>
			<td>D1070</td>
			<td>Gloves and goggles should be worn and operated in a ventilated kitchen. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.</td>
		</tr>
		<tr>
			<td>EDTA-2Na</td>
			<td>KeyGEN BioTECH</td>
			<td>KGT515500</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerin</td>
			<td>HUSHI</td>
			<td>10010618</td>
			<td></td>
		</tr>
		<tr>
			<td>GSH</td>
			<td>Amresco</td>
			<td>0399-250G</td>
			<td></td>
		</tr>
		<tr>
			<td>GSSG</td>
			<td>Amresco</td>
			<td>0524-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Guanidine hydrochloride</td>
			<td>Amresco</td>
			<td>E424-5KG</td>
			<td></td>
		</tr>
		<tr>
			<td>h&#946;2m</td>
			<td>our lab</td>
			<td></td>
			<td>Zhang, S. et al. Structural basis of cross-allele presentation by HLA-A*0301 and HLA-A*1101 revealed by two HIV-derived peptide complexes. Mol Immunol. 49 (1-2), 395-401, (2011).</td>
		</tr>
		<tr>
			<td>IPTG</td>
			<td>Inalco</td>
			<td>1758-1400</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Arginine Hydrochloride</td>
			<td>Amresco</td>
			<td>0877-5KG</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Solarbio</td>
			<td>S8210</td>
			<td></td>
		</tr>
		<tr>
			<td>Protein Marker</td>
			<td>Fermentas</td>
			<td>26614</td>
			<td></td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>Boao Rui Jing</td>
			<td>A112130</td>
			<td></td>
		</tr>
		<tr>
			<td>Superdex Increase 200 10/300 GL</td>
			<td>GE Healthcare</td>
			<td>28990944</td>
			<td></td>
		</tr>
		<tr>
			<td>TEMED</td>
			<td>Thermo</td>
			<td>17919</td>
			<td>Gloves and goggles should be worn and operated in a ventilated kitchen.</td>
		</tr>
		<tr>
			<td>Tris-HCl</td>
			<td>Amresco</td>
			<td>0497-5KG</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Bioruler</td>
			<td>RH30056-100mL</td>
			<td></td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Oxoid</td>
			<td>LP0042</td>
			<td></td>
		</tr>
		<tr>
			<td>Yeast extract</td>
			<td>Oxoid</td>
			<td>LP0021</td>
			<td></td>
		</tr>
	</tbody>
</table>

stability and structure of bat major histocompatibility complex class i with heterologous &beta;2-microglobulin

The major histocompatibility complex (MHC) plays a pivotal role in antigen peptide presentation and T cell immune responses against infectious disease and tumor development. The hybrid MHC I complexed with heterologous &#946;2-microglobulin (&#946;2m) substitution from different species can be stabilized in vitro. This is a feasible means to study MHC I of mammals, when the homologous &#946;2m is not available. Meanwhile, it is indicated that mammalian &#946;2m substitution does not significantly affect peptide presentation. However, there is limited summarization regarding the methodology and the technology for the hybrid MHC I complexed with heterologous &#946;2-microglobulin (&#946;2m). Herein, methods to evaluate the feasibility of heterologous &#946;2m substitution in MHC I study are presented. These methods include preparation of expression constructs; purification of inclusion bodies and refolding of the MHC complex; determination of protein thermostability; crystal screening and structure determination. This study provides a recommendation for understanding function and structure of MHC I, and is also significant for T cell response evaluation during infectious disease and tumor immunotherapy.

Previous work reported that the HeV-derived HeV1 (DFANTFLP) peptide was presented by Ptal-N*01:0110,19. Herein, the binding capacity of this peptide to Ptal-N*01:01 with homologous bat &#946;2m (b&#946;2<font face="Helvetica Neue...

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Stability and Structure of Bat Major Histocompatibility Complex Class I with Heterologous &amp;#946;2-Microglobulin

The protocol describes experimental methods to obtain stable major histocompatibility complex (MHC) class I through potential &#946;2-microglobulin (&#946;2m) substitutions from different species. The structural comparison of MHC I stabilized by homologous and heterologous &#946;2m were investigated.

Stability and Structure of Bat Major Histocompatibility Complex Class I with Heterologous &beta;2-Microglobulin

The major histocompatibility complex (MHC) plays a pivotal role in antigen peptide presentation and T cell immune responses against infectious disease and ...

In this study, we used Bat MHC Class I as a model to summarize the methodology, and to evaluate the feasibility of a hybrid MHC class I complexed with heterologous beta-2 microglobulin. Previous studies have shown that the mammalian B2M substitution does not significantly affect the peptide presentation. In fact, the hybrid MHC Class I can activate a similar structure and function to the original molecule.These techniques can be used to facilitate the functional and structured study of MHC I for tissue response evaluation during infectious disease and tumor immunotherapy. For E.coli culture transformation add 10 nanograms of plasmid containing bat or human MHC Class I beta two microglobulin hydrogen chain to 100 microliters of equalized suspension and bathe the suspension in ice for 30 minutes. At the end of the incubation, heat shock the bacteria for 90 seconds at 42 degrees Celsius, and return the culture to the ice bath for two minutes.Next add 800 microliters of lysogeny broth to the culture, and shake the suspension on a rocking platform for 20 minutes at 37 degrees Celsius, and 200 rotations per minute. At the end of the incubation, spread 100 microliters of the bacteria onto an appropriate antibiotic resistant culture blade. The next morning, pick a single recently transformed bacterial clone and inoculate the clone with three milliliters of LB with antibiotic medium.Place the culture on the rocking platform at 37 degrees Celsius for 12 to 16 hours. The next morning, transfer 500 microliters of the activated bacterial stock into 50 milliliters of LB with antibiotic medium, and return the bacteria to the rocking incubator overnight. Split the remaining activated bacterial stock into 500 microliter aliquots and add each aliquot to 500 microliter volumes of 40%glycerol, for minus 80 degrees Celsius storage.To generate large amounts of recombinant protein, the next morning transfer the bacterial suspension into two liters of LB with antibiotic medium at a one to 100 ratio, and return the culture to the rocking incubator until an absorbance of 0.6 at 600 nanometers is achieved. Then, add one millimolar IPTG to the culture to induce expression of the trans gene. After four to six hours of induction, transfer the bacterial culture to bottles for centrifugation, and re-suspend the bacterial cell pellets in 60 milliliters of PBS per bottle.Then liberate the expressed recombinant protein by ultrasonic cell disruptor 99 times, for six seconds and an interval of 12 seconds at 300 Watts per sonication. For inclusion body purification collect the sonicated bacteria by centrifugation and re-suspend the pellets in an appropriate volume of washing buffer for two additional centrifugations. After the second wash, re-suspend the inclusion bodies and re-suspension buffer, and set aside a 20 microliter aliquot of the sample for SDS page to test the inclusion body purity.Centrifuge the remaining sample, and weigh the inclusion body containing pellet. Add dissolution buffer to the pellets to a final concentration of 30 milligrams of inclusion body per milliliter of buffer. And use a magnetic stirrer to slowly stir the solution at four degrees Celsius, until the inclusion bodies are dissolved in the dissolution buffer.After discarding the precipitates, store the inclusion bodies at minus 20 or minus 80 degrees Celsius. For MHC complex refolding, add a five millimolar reduced glutathione and 0.5 millimolar oxidized glutathione at 250 to 300 milliliters, a four degrees Celsius refolding buffer. And slowly stir the solution on a magnetic stirrer at four degrees Celsius for 10 to 20 minutes.For MHC hydrogen chain and beta two microglobulin dilution, load the inclusion body in a one milliliter syringe and inject the entire one milliliter volume of inclusion body solution into one liter of refolding buffer near the stir bar, to obtain a fast and efficient dilution. Next, dissolve five milligrams per milliliter of peptide in dimethyl sulphoxide, and quickly inject 200 microliters of peptide into the refolding solution as just demonstrated. After 10 to 20 minutes of slow stirring, inject three milliliters of H chain inclusion bodies into a new one liter volume of refolding buffer and allow the refolding to proceed at four degrees Celsius for eight to 10 hours.To determine the refolded protein concentration add exchange buffer to a pressurized chamber with a 10 kilodalton multi copper oxidase membrane, and concentrate the buffer to 30 to 50 milliliter volume. Transfer the refolding solution to a centrifuge tube, and remove the precipitates by centrifugation. Carefully transfer the supernate into the chamber and further concentrate the buffer to a final volume of approximately one milliliter.Remove any final contaminants by centrifugation and transfer the supernate into a sterile tube. Use a ten three hundred GL size exclusion column to purify the proteins, collecting the samples at the peak, and analyzing them using SDS page. Collect the MHC complex peak and concentrate the protein to a final concentration of 15 milligrams per milliliter.Then dilute the complex to 7.5 milligrams per milliliter concentration. To perform crystallization of the complex MHC and peptide using the sitting drop vapor diffusion technique, add 0.8 microliters of the sample to a commercial crystal board and seal the board. Equilibrate the sample solution against 100 microliters of reservoir solution at four or 18 degrees Celsius, and use a microscope to regularly observe the crystal growth over the next six months.For cryogenic protection, at the end of the experiment, transfer the crystals to a storage solution containing 20%glycerol before rapidly cooling the samples in a 100 degree Kelvin gaseous nitrogen stream. Then collect x-ray diffraction data according to standard protocols. To determine the structure of the crystal complexes, open the high resolution structural x-ray diffraction data in the Denzo program within the HK L 2000 software package, and select an initial model in the protein data bank.To determine the structure of the protein, open the data in the Phaser MR Program in CCP4, and use the refined x-ray model for the initial joint refinement. Then use the Phoenix refine alone and joint modes for the x-ray alone refinement, and the joint neutron for the x-ray refinement. After each round of refinement, manually check the model against the Fo-Fc, and 2Fo-Fc positive nuclear density maps in Coot.In these representative experiments, the binding capacities of the Hendra Virus derived Hendra Virus One peptide to bat MHC Class I hydrogen chains with homologous bat beta two microglobulin and heterologous human beta two microglobulin were evaluated. In both analysis, crystals with a high resolution were formed through renaturation with the beta two microglobulin light chain. In the absence of beta two microglobulin, these complexes do not form.In the MHC Class I hydrogen chain Hendra Virus one, human beta two microglobulin structure, conserved residues H31, D53, W60, and Y63 of human beta two microglobulin, which correspond to bat beta two microglobulin, make contact with the bottom of the peptide binding groove and conserved Q8, Y10, R12, and 24 residues, which correspond to the beta two microglobulins bound to the alpha three domain. In the overall bat and human structures, the average root mean square derivation of residues one to 184 of the hydrogen chains is 0.248 under all of the carbon alpha atom's superpositions, indicating that there are no differences between these two complexes. The structure of the peptide alignment shows that the confirmations of Hendra Virus one peptides in these two complexes are quite similar.Sequence alignment also shows that the amino acids of beta two microglobulin from different species are highly conserved. It is important to offer the adversary complexes with a high reporting efficiency. Therefore, it is crucial to select suitable beta two micro globulin and to use highly purified inclusion bodies.This protocol can be used to obtain stable MTC I complex through potential beta two microglobulin substitutions in other species, and to exist they are MTC I structure and function. The data obtained from these studies can be used to assess T-cell responses during infectious disease and tumor immunotherapies.

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Research

JoVE Journal

Immunology and Infection

Induction and Assessment of Class Switch Recombination in Purified Murine B Cells

Humoral immunity is the branch of the immune system maintained by B cells and mediated through the secretion of antibodies. Upon B cell activation, the immunoglobulin locus undergoes a series of genetic modifications to alter the binding capacity and effector function of secreted antibodies. This process is highlighted by a genomic recombination event known as class switch recombination (CSR) in which the default IgM antibody isotype is substituted for one of IgG, IgA, or IgE. Each isotype possesses distinct effector functions thereby making CSR crucial to the maintenance of immunity. Diversification of the immunoglobulin locus is mediated by the enzyme activation-induced cytidine deaminase (AID). A schematic video describing this process in detail is available online (http://video.med.utoronto.ca/videoprojects/immunology/aam.html). AID's activity and the CSR pathway are commonly studied in the assessment of B cell function and humoral immunity in mice. The protocol outlined in this report presents a method of B cell isolation from murine spleens and subsequent stimulation with bacterial lipopolysaccharide (LPS) to induce class switching to IgG3 (for other antibody isotypes see Table 1). In addition, the fluorescent cell staining dye Carboxyfluorescein succinimidyl ester (CFSE) is used to monitor cell division of stimulated cells, a process crucial to isotype switching 1, 2. The regulation of AID and the mechanism by which CSR occurs are still unclear and thus in vitro class switch assays provide a reliable method for testing these processes in various mouse models. These assays have been previously used in the context of gene deficiency using knockout mice 3. Furthermore, in vitro switching of B cells can be preceded by viral transduction to modulate gene expression by RNA knockdown or transgene expression 4-6. The data from these types of experiments have impacted our understanding of AID activity, resolution of the CSR reaction, and antibody-mediated immunity in the mouse.

Following antigen exposure, subpopulations of activated B cells undergo a process known as class switch recombination (CSR) to produce antibody isotypes with distinct effector functions. The protocol outlined in this report explains how CSR can be induced and analyzed in vitro for the purposes of studying B cell function.

Humoral immunity is the branch of the immune system maintained by B cells and mediated through the secretion of antibodies. Upon B cell activation, the ...

Microwave Assisted Rapid Diagnosis of Plant Virus Diseases by Transmission Electron Microscopy

Investigations of ultrastructural changes induced by viruses are often necessary to clearly identify viral diseases in plants. With conventional sample preparation for transmission electron microscopy (TEM) such investigations can take several days1,2 and are therefore not suited for a rapid diagnosis of plant virus diseases. Microwave fixation can be used to drastically reduce sample preparation time for TEM investigations with similar ultrastructural results as observed after conventionally sample preparation3-5. Many different custom made microwave devices are currently available which can be used for the successful fixation and embedding of biological samples for TEM investigations5-8. In this study we demonstrate on Tobacco Mosaic Virus (TMV) infected Nicotiana tabacum plants that it is possible to diagnose ultrastructural alterations in leaves in about half a day by using microwave assisted sample preparation for TEM. We have chosen to perform this study with a commercially available microwave device as it performs sample preparation almost fully automatically5 in contrast to the other available devices where many steps still have to be performed manually6-8 and are therefore more time and labor consuming. As sample preparation is performed fully automatically negative staining of viral particles in the sap of the remaining TMV-infected leaves and the following examination of ultrastructure and size can be performed during fixation and embedding.

This study describes a method that allows the rapid and clear diagnosis of plant virus diseases in about half a day by using a combination of microwave assisted plant sample preparation for transmission electron microscopy and negative staining methods.

Investigations of ultrastructural changes induced by viruses are often necessary to clearly identify viral diseases in plants. With conventional sample ...

Multi-target Parallel Processing Approach for Gene-to-structure Determination of the Influenza Polymerase PB2 Subunit

Pandemic outbreaks of highly virulent influenza strains can cause widespread morbidity and mortality in human populations worldwide. In the United States alone, an average of 41,400 deaths and 1.86 million hospitalizations are caused by influenza virus infection each year 1. Point mutations in the polymerase basic protein 2 subunit (PB2) have been linked to the adaptation of the viral infection in humans 2. Findings from such studies have revealed the biological significance of PB2 as a virulence factor, thus highlighting its potential as an antiviral drug target.
The structural genomics program put forth by the National Institute of Allergy and Infectious Disease (NIAID) provides funding to Emerald Bio and three other Pacific Northwest institutions that together make up the Seattle Structural Genomics Center for Infectious Disease (SSGCID). The SSGCID is dedicated to providing the scientific community with three-dimensional protein structures of NIAID category A-C pathogens. Making such structural information available to the scientific community serves to accelerate structure-based drug design.
Structure-based drug design plays an important role in drug development. Pursuing multiple targets in parallel greatly increases the chance of success for new lead discovery by targeting a pathway or an entire protein family. Emerald Bio has developed a high-throughput, multi-target parallel processing pipeline (MTPP) for gene-to-structure determination to support the consortium. Here we describe the protocols used to determine the structure of the PB2 subunit from four different influenza A strains.

Structure-based drug design plays an important role in drug development. Pursuing multiple targets in parallel greatly increases the chance of success for lead discovery. The following article highlights how the Seattle Structural Genomics Center for Infectious Disease utilizes a multi-target approach for gene-to-structure determination of the PB2 influenza A subunit.

Pandemic outbreaks of highly virulent influenza strains can cause widespread morbidity and mortality in human populations worldwide. In the United States ...

In Situ Detection of Autoreactive CD4 T Cells in Brain and Heart Using Major Histocompatibility Complex Class II Dextramers

This report demonstrates the use of major histocompatibility complex (MHC) class II dextramers for detection of autoreactive CD4 T cells in situ in myelin proteolipid protein (PLP) 139-151-induced experimental autoimmune encephalomyelitis (EAE) in SJL mice and cardiac myosin heavy chain-&#945; (Myhc) 334-352-induced experimental autoimmune myocarditis (EAM) in A/J mice. Two sets of cocktails of dextramer reagents were used, where dextramers+ cells were analyzed by laser scanning confocal microscope (LSCM): EAE, IAs/PLP 139-151 dextramers (specific)/anti-CD4 and IAs/Theiler&#8217;s murine encephalomyelitis virus (TMEV) 70-86 dextramers (control)/anti-CD4; and EAM, IAk/Myhc 334-352 dextramers/anti-CD4 and IAk/bovine ribonuclease (RNase) 43-56 dextramers (control)/anti-CD4. LSCM analysis of brain sections obtained from EAE mice showed the presence of cells positive for CD4 and PLP 139-151 dextramers, but not TMEV 70-86 dextramers suggesting that the staining obtained with PLP 139-151 dextramers was specific. Likewise, heart sections prepared from EAM mice also revealed the presence of Myhc 334-352, but not RNase 43-56-dextramer+ cells as expected. Further, a comprehensive method has also been devised to quantitatively analyze the frequencies of antigen-specific CD4 T cells in the &#8216;Z&#8217; serial images.

In Situ Detection of Autoreactive CD4 T Cells in Brain and Heart Using Major Histocompatibility Complex Class II Dextramers

The protocol to detect self-reactive CD4 T cells in brain and heart by direct staining with major histocompatibility complex class II dextramers has been described in this report. For comprehensive analysis, a reliable method to enumerate the frequencies of antigen-specific CD4+ T cells in situ is also devised.

This report demonstrates the use of major histocompatibility complex (MHC) class II dextramers for detection of autoreactive CD4 T cells in situ in myelin ...

Analysis of Lymphocyte Extravasation Using an In Vitro Model of the Human Blood-brain Barrier

Lymphocyte extravasation into the central nervous system (CNS) is critical for immune surveillance. Disease-related alterations of lymphocyte extravasation might result in pathophysiological changes in the CNS. Thus, investigation of lymphocyte migration into the CNS is important to understand inflammatory CNS diseases and to develop new therapy approaches. Here we present an in vitro model of the human blood-brain barrier to study lymphocyte extravasation. Human brain microvascular endothelial cells (HBMEC) are confluently grown on a porous polyethylene terephthalate transwell insert to mimic the endothelium of the blood-brain barrier. Barrier function is validated by zonula occludens immunohistochemistry, transendothelial electrical resistance (TEER) measurements as well as analysis of evans blue permeation. This model allows investigation of the diapedesis of rare lymphocyte subsets such as CD56brightCD16dim/- NK cells. Furthermore, the effects of other cells, cytokines and chemokines, disease-related alterations, and distinct treatment regimens on the migratory capacity of lymphocytes can be studied. Finally, the impact of inflammatory stimuli as well as different treatment regimens on the endothelial barrier can be analyzed.

Analysis of Lymphocyte Extravasation Using an In Vitro Model of the Human Blood-brain Barrier

Here, we describe a human blood-brain barrier model enabling to investigate lymphocyte transmigration into the central nervous system in vitro.

Lymphocyte extravasation into the central nervous system (CNS) is critical for immune surveillance. Disease-related alterations of lymphocyte ...

An Efficient and Simple Method to Establish NK and T Cell Lines from Patients with Chronic Active Epstein-Barr Virus Infection

A number of methods have been described to establish NK/T cell lines from patients with lymphoma or lymphoproliferative syndrome. These methods employed feeder cells, purified NK or T cells with as much as 10 mL of blood, or a high-dose of IL-2. This study presents a new method with a powerful and simple strategy to establish NK and T cell lines by culturing the peripheral blood mononuclear cells (PBMC) with the addition of recombinant human IL-2 (rhIL-2), and uses as little as 2 mL of whole blood. The cells can proliferate quickly in two weeks and be maintained for more than 3 months. With this method, 7 NK or T cell lines have been established with a high success rate. This method is simple, reliable, and applicable to establishing cell lines from more cases of CAEBV or NK/T cell lymphoma.

A simple method for obtaining NK and T cell clones from CAEBV patients was developed with high efficiency, a small amount of peripheral blood, and a low-dose of IL-2.

A number of methods have been described to establish NK/T cell lines from patients with lymphoma or lymphoproliferative syndrome. These methods employed ...

Opsonophagocytic Killing Assay to Assess Immunological Responses Against Bacterial Pathogens

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental procedure in which phagocytic cells are co-cultured with bacterial units. The immune cells will phagocytose and kill the bacterial cultures in a complement-dependent manner. The efficiency of the immune-mediated cell killing is dependent on a number of factors and can be used to determine how different bacterial cultures compare with regard to resistance to cell death. In this way, the efficacy of potential immune-based therapeutics can be assessed against specific bacterial strains and/or serotypes. In this protocol, we describe a simplified OPKA that utilizes basic culture conditions and cell counting to determine bacterial cell viability after co-culture with treatment conditions and HL-60 immune cells. This method has been successfully utilized with a number of different pneumococcal serotypes, capsular and acapsular strains, and other bacterial species. The advantages of this OPKA protocol are its simplicity, versatility (as this assay is not limited to antibody treatments as opsonins), and minimization of time and reagents to assess basic experimental groups.

This opsonophagocytic killing assay is used to compare the ability of phagocytic immune cells to respond to and kill bacteria based on different treatments and/or conditions. Classically, this assay serves as the gold&#160;standard for assessing effector functions of antibodies raised against a bacterium as opsonin.

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental ...

Application of Consistent Massage-Like Perturbations on Mouse Calves and Monitoring the Resulting Intramuscular Pressure Changes

Massage is generally recognized to be beneficial for relieving pain and inflammation. Although previous studies have reported anti-inflammatory effects of massage on skeletal muscles, the molecular mechanisms behind are poorly understood. We have recently developed a simple device to apply local cyclical compression (LCC), which can generate intramuscular pressure waves with varying amplitudes. Using this device, we have demonstrated that LCC modulates inflammatory responses of macrophages in situ and alleviates immobilization-induced muscle atrophy. Here, we describe protocols for the optimization and application of LCC as a massage-like intervention against immobilization-induced inflammation and atrophy of skeletal muscles of mouse hindlimbs. The protocol that we have developed can be useful for investigating the mechanism underlying beneficial effects of physical exercise and massage. Our experimental system provides a prototype of the analytical approach to elucidate the mechanical regulation of muscle homeostasis, although further development needs to be made for more comprehensive studies.

Here we describe the protocols for applying defined mechanical loads to mouse calves and for monitoring the concomitant intramuscular pressure changes. The experimental systems that we have developed can be useful for investigating the mechanism behind the beneficial effects of physical exercise and massage.

Massage is generally recognized to be beneficial for relieving pain and inflammation. Although previous studies have reported anti-inflammatory effects of ...

Assessing the Expression of Major Histocompatibility Complex Class I on Primary Murine Hippocampal Neurons by Flow Cytometry

Increasing evidence supports the hypothesis that neuro-immune interactions impact nervous system function in both homeostatic and pathologic conditions. A well-studied function of major histocompatibility complex class I (MHCI) is the presentation of cell-derived peptides to the adaptive immune system, particularly in response to infection. More recently it has been shown that the expression of MHCI molecules on neurons can modulate activity-dependent changes in the synaptic connectivity during normal development and neurologic disorders. The importance of these functions to the brain health supports the need for a sensitive assay that readily detects MHCI expression on neurons. Here we describe a method for primary culture of murine hippocampal neurons and then assessment of MHCI expression by flow cytometric analysis. Murine hippocampus is microdissected from prenatal mouse pups at the embryonic day 18. Tissue is dissociated into a single cell suspension using enzymatic and mechanical techniques, then cultured in a serum-free media that limits growth of non-neuronal cells. After 7 days in vitro, MHCI expression is stimulated by treating cultured cells pharmacologically with beta interferon. MHCI molecules are labeled in situ with a fluorescently tagged antibody, then cells are non-enzymatically dissociated into a single cell suspension. To confirm the neuronal identity, cells are fixed with paraformaldehyde, permeabilized, and labeled with a fluorescently tagged antibody that recognizes neuronal nuclear antigen NeuN. MHCI expression is then quantified on neurons by flow cytometric analysis. Neuronal cultures can easily be manipulated by either genetic modifications or pharmacologic interventions to test specific hypotheses. With slight modifications, these methods can be used to culture other neuronal populations or to assess expression of other proteins of interest.

This protocol describes a method for culturing primary hippocampal neurons from embryonic mouse brain. The expression of major histocompatibility complex class I on the extracellular surface of cultured neurons is then assessed by flow cytometric analysis.

Increasing evidence supports the hypothesis that neuro-immune interactions impact nervous system function in both homeostatic and pathologic conditions. A ...

Separation of Immune Cell Subpopulations in Peripheral Blood Samples from Children with Infectious Mononucleosis

Infectious mononucleosis (IM) is an acute syndrome mostly associated with primary Epstein&#8211;Barr virus (EBV) infection. The main clinical symptoms include irregular fever, lymphadenopathy, and significantly increased lymphocytes in peripheral blood. The pathogenic mechanism of IM is still unclear; there is no effective treatment method for it, with mainly symptomatic therapies being available. The main question in EBV immunobiology is why only a small subset of infected individuals shows severe clinical symptoms and even develop EBV-associated malignancies, whilemost individuals are asymptomatic for life with the virus.
B cells are first involved in IM because EBV receptors are presented on their surface. Natural killer (NK) cells are cytotoxic innate lymphocytes that are important for killing EBV-infected cells. The proportion of CD4+ T cells decreases while that of CD8+ T cells expands dramatically during acute EBV infection, and the persistence of CD8+ T cells is important for lifelong control of IM. Those immune cells play important roles in IM, and their functions need to be identified separately. For this purpose, monocytes are separated first from peripheral blood mononuclear cells (PBMCs) of IM individuals using CD14 microbeads, a column, and a magnetic separator.
The remaining PBMCs are stained with peridinin-chlorophyll-protein (PerCP)/Cyanine 5.5 anti-CD3, allophycocyanin (APC)/Cyanine 7 anti-CD4, phycoerythrin (PE) anti-CD8, fluorescein isothiocyanate (FITC) anti-CD19, APC anti-CD56, and APC anti-CD16 antibodies to sort CD4+ T cells, CD8+ T cells, B cells, and NK cells using a flow cytometer. Furthermore, transcriptome sequencing of five subpopulations was performed to explore their functions and pathogenic mechanisms in IM.

We describe a method combining immunomagnetic beads and fluorescence-activated cell sorting to isolate and analyze defined immune cell subpopulations of peripheral blood mononuclear cells (monocytes, CD4+ T cells, CD8+ T cells, B cells, and natural killer cells). Using this method, magnetic and fluorescently labeled cells can be purified and analyzed.

Infectious mononucleosis (IM) is an acute syndrome mostly associated with primary Epstein&#8211;Barr virus (EBV) infection. The main clinical symptoms ...