Name: overlapping peptide library to map qa-1 epitopes in a protein
Uploaded: 2017-12-20T12:30:00
Description: Watch this Scientific Journal Video about Overlapping Peptide Library to Map Qa-1 Epitopes in a Protein at JoVE.com

We thank Penelope Garcia for her technical assistance and preparation of this manuscript. This work was supported by a Research Innovation Grant (RIG) from the Department of Medicine at Loma Linda University (681205-2967) and a pilot grant from National Multiple Sclerosis Society (PP1685) to XT.

All experiments were done in compliance with an Institutional Animal Care and Use Protocol approved by Animal Care and Use Committee at the University of Texas at El Paso and Loma Linda University.
1. Generation of an OLP Library Covering the Whole Length of a Protein
<ol>
	<li>Design an OLP library in which all peptides are 15-mer in length, and adjacent peptides overlap by 11 amino acids. 
	NOTE: In the MOG OLP study, sequence of the MOG precursor [Mus musculus] was retrieved from NCB...

<ol>
	<li>Aldrich, C. 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=Identification+of+a+Tap-dependent+leader+peptide+recognized+by+alloreactive+T+cells+specific+for+a+class+Ib+antigen.">Identification of a Tap-dependent leader peptide recognized by alloreactive T cells specific for a class Ib antigen.</a> Cell. 79 (4), 649-658 (1994).</li><li>Vance, R. E., Kraft, J. R., Altman, J. D., Jensen, P. E., Raulet, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+CD94/NKG2A+is+a+natural+killer+cell+receptor+for+the+nonclassical+major+histocompatibility+complex+(MHC)+class+I+molecule+Qa-1(b).">Mouse CD94/NKG2A is a natural killer cell receptor for the nonclassical major histocompatibility complex (MHC) class I molecule Qa-1(b).</a> J Exp Med. 188 (10), 1841-1848 (1998).</li><li>Oliveira, C. C., 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=The+nonpolymorphic+MHC+Qa-1+mediates+CD8++T+cell+surveillance+of+antigen-processing+defects.">The nonpolymorphic MHC Qa-1 mediates CD8+ T cell surveillance of antigen-processing defects.</a> J Exp Med. 207 (1), 207-221 (2010).</li><li>Nagarajan, N. A., Gonzalez, F., Shastri, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonclassical+MHC+class+Ib-restricted+cytotoxic+T+cells+monitor+antigen+processing+in+the+endoplasmic+reticulum.">Nonclassical MHC class Ib-restricted cytotoxic T cells monitor antigen processing in the endoplasmic reticulum.</a> Nat Immunol. 13 (6), 579-586 (2012).</li><li>Hu, D., 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=Analysis+of+regulatory+CD8+T+cells+in+Qa-1-deficient+mice.">Analysis of regulatory CD8 T cells in Qa-1-deficient mice.</a> Nat Immunol. 5 (5), 516-523 (2004).</li><li>Tang, X., 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=Regulation+of+immunity+by+a+novel+population+of+Qa-1-restricted+CD8alphaalpha+TCRalphabeta++T+cells.">Regulation of immunity by a novel population of Qa-1-restricted CD8alphaalpha+TCRalphabeta+ T cells.</a> J Immunol. 177 (11), 7645-7655 (2006).</li><li>Leavenworth, J. W., Tang, X., Kim, H. J., Wang, X., Cantor, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amelioration+of+arthritis+through+mobilization+of+peptide-specific+CD8++regulatory+T+cells.">Amelioration of arthritis through mobilization of peptide-specific CD8+ regulatory T cells.</a> J Clin Invest. 123 (3), 1382-1389 (2013).</li><li>Wu, Y., Zheng, Z., Jiang, Y., Chess, L., Jiang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+specificity+of+T+cell+regulation+that+enables+self-nonself+discrimination+in+the+periphery.">The specificity of T cell regulation that enables self-nonself discrimination in the periphery.</a> Proc Natl Acad Sci U S A. 106 (2), 534-539 (2009).</li><li>Panoutsakopoulou, 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=Suppression+of+autoimmune+disease+after+vaccination+with+autoreactive+T+cells+that+express+Qa-1+peptide+complexes.">Suppression of autoimmune disease after vaccination with autoreactive T cells that express Qa-1 peptide complexes.</a> J Clin Invest. 113 (8), 1218-1224 (2004).</li><li>Tang, X., Maricic, I., Kumar, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-TCR+antibody+treatment+activates+a+novel+population+of+nonintestinal+CD8+alpha+alpha++TCR+alpha+beta++regulatory+T+cells+and+prevents+experimental+autoimmune+encephalomyelitis.">Anti-TCR antibody treatment activates a novel population of nonintestinal CD8 alpha alpha+ TCR alpha beta+ regulatory T cells and prevents experimental autoimmune encephalomyelitis.</a> J Immunol. 178 (10), 6043-6050 (2007).</li><li>Holderried, T. A., Lang, P. A., Kim, H. J., Cantor, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+disruption+of+CD8++Treg+activity+enhances+the+immune+response+to+viral+infection.">Genetic disruption of CD8+ Treg activity enhances the immune response to viral infection.</a> Proc Natl Acad Sci U S A. 110 (52), 21089-21094 (2013).</li><li>Wang, X., 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=Targeting+Non-classical+Myelin+Epitopes+to+Treat+Experimental+Autoimmune+Encephalomyelitis.">Targeting Non-classical Myelin Epitopes to Treat Experimental Autoimmune Encephalomyelitis.</a> Sci Rep. 6, 36064 (2016).</li><li>Lo, W. F., Dunn, C. D., Ong, H., Metcalf, E. S., Soloski, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+and+host+factors+involved+in+the+major+histocompatibility+complex+class+Ib-restricted+presentation+of+Salmonella+Hsp+60:+novel+pathway.">Bacterial and host factors involved in the major histocompatibility complex class Ib-restricted presentation of Salmonella Hsp 60: novel pathway.</a> Infect Immun. 72 (5), 2843-2849 (2004).</li><li>Xu, W., 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=The+nucleocapsid+protein+of+Rift+Valley+fever+virus+is+a+potent+human+CD8++T+cell+antigen+and+elicits+memory+responses.">The nucleocapsid protein of Rift Valley fever virus is a potent human CD8+ T cell antigen and elicits memory responses.</a> PLoS One. 8 (3), e59210 (2013).</li><li>Schumacher, T. N., 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=Peptide+selection+by+MHC+class+I+molecules.">Peptide selection by MHC class I molecules.</a> Nature. 350 (6320), 703-706 (1991).</li><li>Zhang, X., Goncalves, R., Mosser, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+isolation+and+characterization+of+murine+macrophages.">The isolation and characterization of murine macrophages.</a> Curr Protoc Immunol. , (2008).</li><li>Guo, H. C., 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=Different+length+peptides+bind+to+HLA-Aw68+similarly+at+their+ends+but+bulge+out+in+the+middle.">Different length peptides bind to HLA-Aw68 similarly at their ends but bulge out in the middle.</a> Nature. 360 (6402), 364-366 (1992).</li><li>Soloski, M. J., Metcalf, E. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+involvement+of+class+Ib+molecules+in+the+host+response+to+infection+with+Salmonella+and+its+relevance+to+autoimmunity.">The involvement of class Ib molecules in the host response to infection with Salmonella and its relevance to autoimmunity.</a> Microbes Infect. 3 (14-15), 1249-1259 (2001).</li><li>Smith, T. R., 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=Dendritic+cells+use+endocytic+pathway+for+cross-priming+class+Ib+MHC-restricted+CD8alphaalpha+TCRalphabeta++T+cells+with+regulatory+properties.">Dendritic cells use endocytic pathway for cross-priming class Ib MHC-restricted CD8alphaalpha+TCRalphabeta+ T cells with regulatory properties.</a> J Immunol. 182 (11), 6959-6968 (2009).</li><li>Kalra, A., Mukherjee, P., Chauhan, V. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+fine+specificity+of+the+immune+response+to+a+Plasmodium+falciparum+rhoptry+neck+protein,+PfAARP.">Characterization of fine specificity of the immune response to a Plasmodium falciparum rhoptry neck protein, PfAARP.</a> Malar J. 15, 457 (2016).</li><li>Kambayashi, T., 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=The+nonclassical+MHC+class+I+molecule+Qa-1+forms+unstable+peptide+complexes.">The nonclassical MHC class I molecule Qa-1 forms unstable peptide complexes.</a> J Immunol. 172 (3), 1661-1669 (2004).</li></ol>

Here, we have described a protocol for analyzing Qa-1 epitopes in a protein. In relation to this protocol, several other strategies were also reported previously. First, allogeneic CD8+ T cell lines and clones were used for the identification of the Qdm1. Second, a putative Qa-1-binding motif from the analysis of Qdm was used for the identification of the HSP60p216-224 and a TCRBV8.1 epitope9,18. Third, individual overlapping pe...

Qa-1 belongs to a group of non-classical major histocompatibility complex 1b (MHC-Ib) molecules in mice. Its human homolog is HLA-E. Previous evidence has demonstrated that Qa-1 molecules have important biological functions. Firstly, Qa-1 molecules play an important role in surveying cells for structural and functional integrity. In this regard, Qa-1 molecules have evolved several strategies to monitor the normal function of a cell. One such strategy enables Qa-1 molecules to form complexes with a processed leader peptide (epitope), i.e. the Qa-1 determinant modifier (Qdm) that is processed from classical MHC-Ia molecules in the endoplasmic reticulum1. These Qa-1/Qdm complexes later display on the surface of a cell and bind to inhibitory NKG2A receptors on NK cells to inhibit NK killing activity2. If the expression of MHC-Ia molecules is lost, a cell (e.g. a malignant cell) becomes sensitive to NK killing2. The other strategy enables Qa-1 molecules to form new Qa-1/epitope complexes on the surface of a cell that is deficient in TAP (transporter associated with antigen processing)3 and/or ERAAP (endoplasmic reticulum aminopeptidase associated with antigen processing)4 (both deficiencies often occur in malignant cells). The cell that expresses these new Qa-1/epitope complexes can then be recognized and eliminated by the epitope-specific Qa-1-restricted CD8+ T cells. Secondly, Qa-1 molecules induce immune regulation5. In this regard, Qa-1/epitope complexes have been shown to stimulate CD8+ regulatory T (Treg) cells that are important for the prevention of immune-mediated damage of self-tissues6,7,8,9,10. Thirdly, Qa-1-restricted CD8+ Treg cells have been shown to limit immune responses against viral infection11.
Therefore, specific augmentation of epitope-specific Qa-1-restrictred CD8+ T cells is a potentially promising strategy for the elimination of abnormal cells, for the enhancement of immune regulation, and for the control of the magnitude of virus-induced immune responses. While it has not been determined whether augmentation of epitope-specific Qa-1-restricted CD8+ T cells can enhance immune surveillance and limit virus-induced immune responses, our laboratories and others have clearly demonstrated that immunization with Qa-1 epitopes can augment the function of Qa-1-restricted CD8+ Treg cells specific for pathogenic autoimmune CD4+ T cells, leading to efficient control of CD4+ T cell-mediated autoimmune diseases in a variety of animal models such as experimental allergic encephalomyelitis (an animal model of human multiple sclerosis)6,10, collagen-induced arthritis (an animal model of human rheumatoid arthritis)7, and non-obese diabetes (an animal model of human type 1 diabetes)8. Additionally, we have discovered that immunization with a tissue-specific Qa-1 epitope leads to specific control of immune-mediated inflammation in that tissue through augmentation of CD8+ Treg cells12. The above successes of preclinical studies indicate a need for a full evaluation of Qa-1 epitope immunization for the treatment of tissue-specific immune-mediated diseases and potentially for the therapy of other diseases associated with deficiencies in TAP and ERAAP.
Accordingly, there is a demand for a technology that can reliably and quickly analyze Qa-1 epitopes in a protein. In this regard, a limited number of biologically important Qa-1 epitopes has been described. Most of these Qa-1 epitopes were identified serendipitously during the study of CD8+ T cell responses to bacteria13, cells deficient in TAP3, cells deficient in ERAAP4, and cells that cause EAE6,9. Therefore, a high throughput technique is desirable for the identification of biologically important Qa-1 epitopes in a defined protein. In the following, we describe an overlapping peptide (OLP) library strategy that maps functional Qa-1 epitopes in a protein using Qa-1-resrticted CD8+ T cell lines specific for the OLP pool (OLP_pool) of a protein.

<table>
	<tbody>
		<tr>
			<td>The protein to be analyzed</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Sequence of the protein can be obtained from NCBI</td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>Sigma-Aldrich</td>
			<td>Cat#: D2650 SIGMA</td>
			<td>DMSO should be sterile and cell culture tested.</td>
		</tr>
		<tr>
			<td>Kb-/-Db-/- mice</td>
			<td>The Lackson Laboratory</td>
			<td>Stock#: 019995</td>
			<td>We used Taconic H2-KbH2-Db doube knockout mice (Cat#: 4215-F and 4215-M) which however are not available anymore.</td>
		</tr>
		<tr>
			<td>AIM V Serum Free Medium</td>
			<td>ThermoFisher Scientific</td>
			<td>Cat#: 12055091</td>
			<td></td>
		</tr>
		<tr>
			<td>2-mercaptoethanol</td>
			<td>ThermoFisher Scientific</td>
			<td>Cat#: 21985023</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium pyruvate</td>
			<td>ThermoFisher Scientific</td>
			<td>Cat#: 11360070</td>
			<td></td>
		</tr>
		<tr>
			<td>Nonessential Amino Acids</td>
			<td>ThermoFisher Scientific</td>
			<td>Cat#: 11140076</td>
			<td></td>
		</tr>
		<tr>
			<td>Dynabeads CD8 Positive Isolation Kit</td>
			<td>ThermoFisher Scientific</td>
			<td>Cat#: 11333D</td>
			<td></td>
		</tr>
		<tr>
			<td>Bio-Gel P-100</td>
			<td>Bio-Rad</td>
			<td>Cat#: 150-4171</td>
			<td></td>
		</tr>
		<tr>
			<td>Phoshate Balanced Solution (PBS)</td>
			<td>ThermoFisher Scientific</td>
			<td>Cat#: 20012027</td>
			<td></td>
		</tr>
		<tr>
			<td>Trasfer pipette</td>
			<td>Globe Scientific</td>
			<td>Mfg#: 137238</td>
			<td></td>
		</tr>
		<tr>
			<td>Murine M-CSF</td>
			<td>PeproTech</td>
			<td>Cat#: 315-02</td>
			<td></td>
		</tr>
		<tr>
			<td>48-well tissue culture plates</td>
			<td>USA Scientific</td>
			<td>Cat#: CC7682-7548</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning Costar TC-treated Multiple well Plates, 96-well, V-shaped bottom</td>
			<td>Sigma-Aldrich</td>
			<td>Cat#: Z372129 Sigma</td>
			<td></td>
		</tr>
		<tr>
			<td>1ml deep 06-well PP plate, sterile</td>
			<td>USA Scientific</td>
			<td>Item#: 1896-1110</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant murine IL-2</td>
			<td>PeproTech</td>
			<td>Cat#: 212-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant murine IL-7</td>
			<td>PeproTech</td>
			<td>Cat#L: 217-17</td>
			<td></td>
		</tr>
		<tr>
			<td>Capture anti-IFN-&#947; antibody</td>
			<td>BD Biosciences</td>
			<td>Cat#: 551881</td>
			<td></td>
		</tr>
		<tr>
			<td>ELISPOT plate</td>
			<td>Sigma-Aldrich</td>
			<td>Cat#: S2EM004M99</td>
			<td></td>
		</tr>
		<tr>
			<td>C1R</td>
			<td>ATCC</td>
			<td>Cat#: ATCC CRL-1993</td>
			<td></td>
		</tr>
		<tr>
			<td>C1R.Qa-1b</td>
			<td></td>
			<td></td>
			<td>Custom made (GenBank access#: NM_010398.3)</td>
		</tr>
		<tr>
			<td>Qa-1 lentiviral vector</td>
			<td>GeneCopoeia</td>
			<td>Product#: Mm02955</td>
			<td></td>
		</tr>
		<tr>
			<td>Detection anti-IFN-&#947; antibody</td>
			<td>BD Biosciences</td>
			<td>Cat#: 551881</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween20</td>
			<td>Sigma-Aldrich</td>
			<td>Cat#: P9416</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptavidin-HRP</td>
			<td>BD Biosciences</td>
			<td>Cat#: BD557630</td>
			<td></td>
		</tr>
		<tr>
			<td>AEC substrate</td>
			<td>BD Biosciences</td>
			<td>Cat#: 551951</td>
			<td></td>
		</tr>
		<tr>
			<td>ImmunoSpot Analyzer</td>
			<td>ImmunoSpot</td>
			<td></td>
			<td>Any immunoSpot analyer should work for this purpose.</td>
		</tr>
	</tbody>
</table>

overlapping peptide library to map qa-1 epitopes in a protein

Qa-1 (HLA-E in human) belongs to a group of non-classical major histocompatibility complex 1b (MHC-Ib) molecules. Recent data suggest that Qa-1 molecules play important roles in surveying cells for structural and functional integrity, inducing immune regulation, and limiting immune responses to viral infections. Additionally, functional augmentation of Qa-1-restricted CD8+ T cells through epitope immunization has shown therapeutic effects in several autoimmune disease animal models, e.g. experimental allergic encephalomyelitis, collagen-induced arthritis, and non-obese diabetes. Therefore, there is an urgent need for a method that can efficiently and quickly identify functional Qa-1 epitopes in a protein. Here, we describe a protocol that utilizes Qa-1-restricted CD8+ T cell lines specific for an overlapping peptide (OLP) library for determining Qa-1 epitopes in a protein. This OLP library contains 15-mer overlapping peptides that cover the whole length of a protein, and adjacent peptides overlap by 11 amino acids. Using this protocol, we recently identified a 9-mer Qa-1 epitope in myelin oligodendrocyte glycoprotein (MOG). This newly mapped MOG Qa-1 epitope was shown to induce epitope-specific, Qa-1-restricted CD8+ T cells that enhanced myelin-specific immune regulation. Therefore, this protocol is useful for future investigation of novel targets and functions of Qa-1-restricted CD8+ T cells.

Design of an OLP library covering the whole length of a protein
Beginning at the N-terminus of a protein, each peptide is 15 amino acids (15-mer). Hence, the first peptide spans position 1 to position 15. The N-terminus of the second peptide overlaps with the C-terminus of the first peptide by 11 amino acid. Hence, the second peptide spans the position 5 to position 19. Design the rest of the peptides to the end of C-terminus of th...

Watch this Scientific Journal Video about Overlapping Peptide Library to Map Qa-1 Epitopes in a Protein at JoVE.com

Overlapping Peptide Library to Map Qa-1 Epitopes in a Protein

Qa-1 (HLA-E in human) belongs to a group of non-classical major histocompatibility complex 1b molecules. Immunization with Qa-1-binding epitopes has been shown to augment tissue-specific immune regulation and ameliorate several autoimmune diseases. Herein we describe an overlapping peptide library strategy for the identification of Qa-1 epitopes in a protein.

Qa-1 (HLA-E in human) belongs to a group of non-classical major histocompatibility complex 1b (MHC-Ib) molecules. Recent data suggest that Qa-1 molecules ...

The overall goal of this procedure is to identify Qa-1 epitopes in proteins. This method can help answer key questions in the field of immune regulation and immunotherapy. The main advantages of this technique are that mapped peptides are known to stimulate Qa-1 restricted CD8 T cells, and the procedure is easy to perform.The implications of this technique extend towards therapeutic designs for immune-mediated diseases, such as multiple sclerosis. Though this method can provide insight into Qa-1 mediated immune regulation in animals, it can also be applied to HLA-E mediated immune regulation in humans. To begin the procedure, design a library of 15-mer peptides, in which adjacent peptides overlap in 11 amino acids.Obtain and reconstitute the peptides under sterile conditions. For each peptide, combine five milligrams of the peptide with 100 microliters of dimethyl sulfoxide. Combine 10 microliters of each peptide stock in a clean 1-milliliter cryo tube to prepare the OLP pool stock.Then, load 20 microliters of each peptide stock into a V-bottomed 96-well plate, and dilute each stock with 80 microliters of sterile water. Store both the remaining 50 milligrams per milliliter peptide stocks and the plate of 10 milligrams per milliliter peptides stocks at 20 degrees Celsius. Next, add 10 microliters of the OLP pool stock solution to a 15 milliliter tube containing two milliliters of irradiated dendritic cells in serum-free medium, thus diluting the DMSO two hundred-fold.Store the remaining OLP pool stock at 20 degrees Celsius. Incubate the DCs with the OLP pool at room temperature for three hours. Gently shake the cells every 15 minutes by hand.During the incubation, use a kit to purify CD8+T cells from a harvested mouse spleen or lymph nodes. Prepare five milliliters of a solution with 10 million T cells per milliliter of serum-free medium with 50 units per milliliter of interleukin 2, and 100 units per milliliter of interleukin 7. The purified CD8 T cells should be free of beads, or untouched.Place 0.5 milliliters of the T-cell solution in each of 10 wells of a 48-well plate. Once the incubation of the OLP pool-pulsed DC solution is complete, add 10 milliliters of serum-free medium to the DCs. Centrifuge the cells at 300 times G for 10 minutes at room temperature.Then, reconstitute the cells in five milliliters of serum-free medium. Add 0.5 milliliters of the cell suspension to each of the 10 wells. Incubate the cells at 37 degrees Celsius in a 5%carbon dioxide atmosphere for four days.Then, remove 400 microliters of the culture medium from each well. Add 500 microliters of fresh serum-free medium containing 100 units per milliliter each of IL-2 and IL-7 to each well. Incubate the cells for another two to three days before re-stimulating the OLP pool-primed cells.Prior to re-stimulation, obtain and irradiate mouse peritoneal macrophages. Adjust the macrophage concentration to five million cells per milliliter of serum-free medium. Combine 10 microliters of the OLP pool stock with two milliliters of the irradiated peritoneal macrophages for a final DMSO concentration of 0.5%by volume.Supplement this solution with 100 units per milliliter of murine macrophage colony-stimulating factor. Fill a 48-well plate with 200 microliters of the OLP-pool macrophage solution in each well. Incubate the plate at 37 degrees Celsius for four hours.Then, gently wash each well with 200 microliters of pre-warmed RPMI-0 medium. The macrophage solution will contain lot of beads. Before the OLP pool-primed CD8 T cells are added, the plate should be checked under a microscope to make sure that all the wells are free of beads.Next, collect and pool the OLP pool-primed CD8+T cells that are ready for re-stimulation. Adjust the T-cell concentration to one million cells per milliliter in serum-free medium containing 25 units per milliliter of IL-2, and 50 units per milliliter of IL-7. Add one milliliter of the pooled T-cell solution to each well containing OLP pool-pulsed macrophages.Culture the cells at 37 degrees Celsius in a 5%carbon dioxide atmosphere for four days. Then, remove about 400 microliters of the medium from each well. Add to each well 500 microliters of fresh serum-free medium containing 100 units per milliliter each of IL-2 and IL-7.Resume incubation under the same conditions. After three to four days, examine the re-stimulated cells for an OLP pool-specific Qa-1 restricted response with an interferon-gamma enzyme linked immuno spot assay. Refresh the CD8+T-cell medium every three to four days while waiting for the results.Perform an ELISPOT assay with the dilute peptide stocks to determine which peptides produce the OLP pool-specific Qa-1 restricted interferon-gamma secretion. Lastly, evaluate a truncated peptide series with ELISPOT to identify the optimal Qa-1 epitope. An interferon-gamma ELISPOT assay showed a significant increase in spot-forming cells when CD8+T cells stimulated by the pooled MOG overlapping peptide library were combined with C1R.Qa-1b cells. This suggested that the T cells responded to the Qa-1 binding peptides, and that the MOG_pool contained one or more Qa-1 binding epitopes. Another assay was performed to screen the individual peptides in the pool.Three peptides showed responses that were at least three times greater than the response in the presence of C1R. Qa-1b cells without peptides. Of these, the peptide with the greatest response was selected for further evaluation.A library of truncated peptides based on the 15-mer peptide of interest was evaluated to identify the optimal Qa-1 epitope. The epitope would ideally be eight to 10 mer, with nine mer preferred. Further, the optimal epitope would show a similar or stronger interferon-gamma response than the 15-mer peptide.The nine mer N-terminally truncated peptide best fit these criteria, making it the optimal Qa-1 epitope. After its development, this technique paved the way for researchers in the field of immune regulation to discover new Qa-1 epitopes for the study of immune regulation in other tissues, such as the pancreas. Don't forget, working with radiation can be extremely hazardous.Researchers should strictly follow the institutional policy and be appropriately trained.

overlapping-peptide-library-to-map-qa-1-epitopes-in-a-protein

Research

JoVE Journal

Immunology and Infection

Use of Interferon-&gamma; Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus

A protocol has been developed to overcome the difficulties of isolating and characterizing rare T cells specific for pathogens, such as human papillomavirus (HPV), that cause localized infections. The steps involved are identifying region(s) of HPV proteins that contain T-cell epitope(s) from a subject, selecting for the peptide-specific T cells based on interferon-&gamma; (IFN-&gamma;) secretion, and growing and characterizing the T-cell clones (Fig. 1). Subject 1 was a patient who was recently diagnosed with a high-grade squamous intraepithelial lesion by biopsy and underwent loop electrical excision procedure for treatment on the day the T cells were collected1. A region within the human papillomavirus type 16 (HPV 16) E6 and E7 proteins which contained a T-cell epitope was identified using an IFN- g enzyme-linked immunospot (ELISPOT) assay performed with overlapping synthetic peptides (Fig. 2). The data from this assay were used not only to identify a region containing a T-cell epitope, but also to estimate the number of epitope specific T cells and to isolate them on the basis of IFN- &gamma; secretion using commercially available magnetic beads (CD8 T-cell isolation kit, Miltenyi Biotec, Auburn CA). The selected IFN-&gamma; secreting T cells were diluted and grown singly in the presence of an irradiated feeder cell mixture in order to support the growth of a single T-cell per well. These T-cell clones were screened using an IFN- &gamma; ELISPOT assay in the presence of peptides covering the identified region and autologous Epstein-Barr virus transformed B-lymphoblastoid cells (LCLs, obtained how described by Walls and Crawford)2 in order to minimize the number of T-cell clone cells needed. Instead of using 1 x 105 cells per well typically used in ELISPOT assays1,3, 1,000 T-cell clone cells in the presence of 1 x 105 autologous LCLs were used, dramatically reducing the number of T-cell clone cells needed. The autologous LCLs served not only to present peptide antigens to the T-cell clone cells, but also to keep a high cell density in the wells allowing the epitope-specific T-cell clone cells to secrete IFN-&gamma;. This assures successful performance of IFN-&gamma; ELISPOT assay. Similarly, IFN- &gamma; ELISPOT assays were utilized to characterize the minimal and optimal amino acid sequence of the CD8 T-cell epitope (HPV 16 E6 52-61 FAFRDLCIVY) and its HLA class I restriction element (B58). The IFN- &gamma; ELISPOT assay was also performed using autologous LCLs infected with vaccinia virus expressing HPV 16 E6 or E7 protein. The result demonstrated that the E6 T-cell epitope was endogenously processed. The cross-recognition of homologous T-cell epitope of other high-risk HPV types was shown. This method can also be used to describe CD4 T-cell epitopes4.

Use of Interferon-&amp;#947; Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus

Characterizing T-cell epitopes of pathogens that cause localized infections such as human papillomavirus is a challenge because of limited number of T cells in circulation. A method is described in which rare T cells were isolated and were characterized starting with a very small number of cells.

A protocol has been developed to overcome the difficulties of isolating and characterizing rare T cells specific for pathogens, such as human ...

Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung

There is growing concern about the relevance of in vitro antimicrobial susceptibility tests when applied to isolates of P. aeruginosa from cystic fibrosis (CF) patients. Existing methods rely on single or a few isolates grown aerobically and planktonically. Predetermined cut-offs are used to define whether the bacteria are sensitive or resistant to any given antibiotic1. However, during chronic lung infections in CF, P. aeruginosa populations exist in biofilms and there is evidence that the environment is largely microaerophilic2. The stark difference in conditions between bacteria in the lung and those during diagnostic testing has called into question the reliability and even relevance of these tests3.
 Artificial sputum medium (ASM) is a culture medium containing the components of CF patient sputum, including amino acids, mucin and free DNA. P. aeruginosa growth in ASM mimics growth during CF infections, with the formation of self-aggregating biofilm structures and population divergence4,5,6. The aim of this study was to develop a microtitre-plate assay to study antimicrobial susceptibility of P. aeruginosa based on growth in ASM, which is applicable to both microaerophilic and aerobic conditions.
 An ASM assay was developed in a microtitre plate format. P. aeruginosa biofilms were allowed to develop for 3 days prior to incubation with antimicrobial agents at different concentrations for 24 hours. After biofilm disruption, cell viability was measured by staining with resazurin. This assay was used to ascertain the sessile cell minimum inhibitory concentration (SMIC) of tobramycin for 15 different P. aeruginosa isolates under aerobic and microaerophilic conditions and SMIC values were compared to those obtained with standard broth growth. Whilst there was some evidence for increased MIC values for isolates grown in ASM when compared to their planktonic counterparts, the biggest differences were found with bacteria tested in microaerophilic conditions, which showed a much increased resistance up to a &gt;128 fold, towards tobramycin in the ASM system when compared to assays carried out in aerobic conditions.
 The lack of association between current susceptibility testing methods and clinical outcome has questioned the validity of current methods3. Several in vitro models have been used previously to study P. aeruginosa biofilms7, 8. However, these methods rely on surface attached biofilms, whereas the ASM biofilms resemble those observed in the CF lung9 . In addition, reduced oxygen concentration in the mucus has been shown to alter the behavior of P. aeruginosa2 and affect antibiotic susceptibility10. Therefore using ASM under microaerophilic conditions may provide a more realistic environment in which to study antimicrobial susceptibility.

Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung

Current diagnostic antimicrobial susceptibility testing relies on the planktonic growth of isolates in nutrient rich, aerobic conditions. Here, we employ an alternative artificial sputum medium to study antimicrobial susceptibility of Pseudomonas aeruginosa biofilms under both aerobic and microaerophilic conditions more representative of the cystic fibrosis lung.

There  is growing concern about the relevance of in vitro antimicrobial  susceptibility tests when applied to isolates of P. aeruginosa from  cystic ...

A Comparative Approach to Characterize the Landscape of Host-Pathogen Protein-Protein Interactions

Significant efforts were gathered to generate large-scale comprehensive protein-protein interaction network maps. This is instrumental to understand the pathogen-host relationships and was essentially performed by genetic screenings in yeast two-hybrid systems. The recent improvement of protein-protein interaction detection by a Gaussia luciferase-based fragment complementation assay now offers the opportunity to develop integrative comparative interactomic approaches necessary to rigorously compare interaction profiles of proteins from different pathogen strain variants against a common set of cellular factors.
This paper specifically focuses on the utility of combining two orthogonal methods to generate protein-protein interaction datasets: yeast two-hybrid (Y2H) and a new assay, high-throughput Gaussia princeps protein complementation assay (HT-GPCA) performed in mammalian cells.
A large-scale identification of cellular partners of a pathogen protein is performed by mating-based yeast two-hybrid screenings of cDNA libraries using multiple pathogen strain variants. A subset of interacting partners selected on a high-confidence statistical scoring is further validated in mammalian cells for pair-wise interactions with the whole set of pathogen variants proteins using HT-GPCA. This combination of two complementary methods improves the robustness of the interaction dataset, and allows the performance of a stringent comparative interaction analysis. Such comparative interactomics constitute a reliable and powerful strategy to decipher any pathogen-host interplays.

This article focuses on the identification of high-confident interaction datasets between host and pathogen proteins using a combination of two orthogonal methods: yeast two-hybrid followed by a high-throughput interaction assay in mammalian cells called HT-GPCA.

Significant efforts were gathered to generate  large-scale comprehensive protein-protein interaction network maps. This is  instrumental to understand the ...

Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species

The investigation of the intracellular protein levels of bacterial species is of importance to understanding the pathogenic mechanisms of diseases caused by these organisms. Here we describe a procedure for protein extraction from Burkholderia species based on mechanical lysis using glass beads in the presence of ethylenediamine tetraacetic acid and phenylmethylsulfonyl fluoride in phosphate buffered saline. This method can be used for different Burkholderia species, for different growth conditions, and it is likely suitable for the use in proteomic studies of other bacteria. Following protein extraction, a two-dimensional (2-D) gel electrophoresis proteomic technique is described to study global changes in the proteomes of these organisms. This method consists of the separation of proteins according to their isoelectric point by isoelectric focusing in the first dimension, followed by separation on the basis of molecular weight by acrylamide gel electrophoresis in the second dimension. Visualization of separated proteins is carried out by silver staining.

Total Protein Extraction and 2-D Gel Electrophoresis Methods for Burkholderia Species

Members of the Burkholderia genus are pathogens of clinical importance. We describe a method for total bacterial protein extraction, using mechanical disruption, and 2-D gel electrophoresis for subsequent proteomic analysis.

The investigation of  the intracellular protein levels of bacterial species is of importance to  understanding the pathogenic mechanisms of diseases ...

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 ...

Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining

Peptide-major histocompatibility complex class I (pMHC-I) tetramers have been an invaluable tool to study CD8+ T-cell responses. Because these reagents directly bind to T-cell receptors on the surface of CD8+ T-lymphocytes, fluorochrome-labeled pMHC-I tetramers enable the accurate detection of antigen (Ag)-specific CD8+ T-cells without the need for in vitro re-stimulation. Moreover, when combined with multi-color flow cytometry, pMHC-I tetramer staining can reveal key aspects of Ag-specific CD8+ T-cells, including differentiation stage, memory phenotype, and activation status. These types of analyses have been especially useful in the field of HIV immunology where CD8+ T-cells can affect progression to AIDS. Experimental infection of rhesus macaques with simian immunodeficiency virus (SIV) provides an invaluable tool to study cellular immunity against the AIDS virus. As a result, considerable progress has been made in defining and characterizing T-cell responses in this animal model. Here we present an optimized protocol for enumerating SIV-specific CD8+ T-cells in rhesus macaques by pMHC-I tetramer staining. Our assay permits the simultaneous quantification and memory phenotyping of two pMHC-I tetramer+ CD8+ T-cell populations per test, which might be useful for tracking SIV-specific CD8+ T-cell responses generated by vaccination or SIV infection. Considering the relevance of nonhuman primates in biomedical research, this methodology is applicable for studying CD8+ T-cell responses in multiple disease settings.

Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining

Here, we present an optimized protocol for enumerating and characterizing rhesus macaque CD8+ T cells against the AIDS virus. This article is useful not only to the field of HIV immunology, but also to other areas of biomedical research where CD8+ T cell responses are known to affect disease outcome.

Peptide-major histocompatibility complex class I (pMHC-I) tetramers have been an invaluable tool to study CD8+ T-cell responses. Because these reagents ...

Peptide Scanning-assisted Identification of a Monoclonal Antibody-recognized Linear B-cell Epitope

The identification of an antigenic epitope by the immune system allows for the understanding of the protective mechanism of neutralizing antibodies that may facilitate the development of vaccines and peptide drugs. Peptide scanning is a simple and efficient method that straightforwardly maps the linear epitope recognized by a monoclonal antibody (mAb). Here, the authors present an epitope determination methodology involving serially truncated recombinant proteins, synthetic peptide design, and dot-blot hybridization for the antigenic recognition of nervous necrosis virus coat protein using a neutralizing mAb. This technique relies on the dot-blot hybridization of synthetic peptides and mAbs on a polyvinylidene fluoride (PVDF) membrane. The minimum antigenic region of a viral coat protein recognized by the RG-M56 mAb can be narrowed down by step-by-step trimmed peptide mapping onto a 6-mer peptide epitope. In addition, alanine scanning mutagenesis and residue substitution can be performed to characterize the binding significance of each amino acid residue making up the epitope. The residues flanking the epitope site were found to play critical roles in peptide conformation regulation. The identified epitope peptide may be used to form crystals of epitope peptide-antibody complexes for an x-ray diffraction study and functional competition, or for therapeutics.

Here, the authors present a simple and efficient protocol to define a linear antigenic epitope using a purified monoclonal antibody and peptide scanning through dot-blot hybridization. The identified epitope can then be used in therapeutic and diagnostic applications.

The identification of an antigenic epitope by the immune system allows for the understanding of the protective mechanism of neutralizing antibodies that ...

Creation of a Dense Transposon Insertion Library Using Bacterial Conjugation in Enterobacterial Strains Such As Escherichia Coli or Shigella flexneri

Transposon mutagenesis is a method that allows gene disruption via the random genomic insertion of a piece of DNA called a transposon. The protocol below outlines a method for high efficiency transfer between bacterial strains of a plasmid harboring a transposon containing a kanamycin resistance marker. The plasmid-borne transposase is encoded by a variant tnp gene that inserts the transposon into the genome of the recipient strain with very low insertional bias. This method thus allows the creation of large mutant libraries in which transposons have been inserted into unique genomic positions in a recipient strain of either Escherichia coli or Shigella flexneri bacteria. By using bacterial conjugation, as opposed to other methods such as electroporation or chemical transformation, large libraries with hundreds of thousands of unique clones can be created. This yields high-density insertion libraries, with insertions occurring as frequently as every 4-6 base pairs in non-essential genes. This method is superior to other methods as it allows for an inexpensive, easy to use, and high efficiency method for the creation of a dense transposon insertion library. The transposon library can be used in downstream applications such as transposon sequencing (Tn-Seq), to infer genetic interaction networks, or more simply, in mutational (forward genetic) screens.

Creation of a Dense Transposon Insertion Library Using Bacterial Conjugation in Enterobacterial Strains Such As Escherichia Coli or Shigella flexneri

Presented here is a simple method for creating a high-density transposon insertion library in Escherichia coli or Shigella flexneri using bacterial conjugation. This protocol allows the creation of a collection of hundreds of thousands of unique mutants in bacteria by the random genomic insertion of a transposon.

Transposon mutagenesis is a method that allows gene disruption via the random genomic insertion of a piece of DNA called a transposon. The protocol below ...

Overexpression and Purification of Human Cis-prenyltransferase in Escherichia coli

Prenyltransferases (PT) are a group of enzymes that catalyze chain elongation of allylic diphosphate using isopentenyl diphosphate (IPP) via multiple condensation reactions. DHDDS (dehydrodolichyl diphosphate synthase) is a eukaryotic long-chain cis-PT (forming cis double bonds from the condensation reaction) that catalyzes chain elongation of farnesyl diphosphate (FPP, an allylic diphosphate) via multiple condensations with isopentenyl diphosphate (IPP). DHDDS is of biomedical importance, as a non-conservative mutation (K42E) in the enzyme results in retinitis pigmentosa, ultimately leading to blindness. Therefore, the present protocol was developed in order to acquire large quantities of purified DHDDS, suitable for mechanistic studies. Here, the usage of protein fusion, optimized culture conditions and codon-optimization were used to allow the overexpression and purification of functionally active human DHDDS in E. coli. The described protocol is simple, cost-effective and time sparing. The homology of cis-PT among different species suggests that this protocol may be applied for other eukaryotic cis-PT as well, such as those involved in natural rubber synthesis.

Overexpression and Purification of Human Cis-prenyltransferase in Escherichia coli

A simple protocol for overexpression and purification of codon-optimized, human cis-prenyltransferase, under non-denaturing conditions, from Escherichia coli, is described, along with an enzymatic activity assay. This protocol can be generalized for production of other cis- prenyltransferase proteins in quantity and quality suitable for mechanistic studies.

Prenyltransferases (PT) are a group of enzymes that catalyze chain elongation of allylic diphosphate using isopentenyl diphosphate (IPP) via multiple ...

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research is deciphering how these dynamic protein complexes act to integrate signals from multiple sources in order to direct a specific biological response, and how this becomes deregulated in many disease settings. Despite the importance of this key biochemical mechanism, there is a lack of experimental techniques that can facilitate the specific and sensitive deconvolution of these multi-molecular signaling complexes.
Here this shortcoming is addressed through the combination of a protein complementation assay with a conformation-specific nanobody, which we have termed Bimolecular Complementation Affinity Purification (BiCAP). This novel technique facilitates the specific isolation and downstream proteomic characterization of any pair of interacting proteins, to the exclusion of un-complexed individual proteins and complexes formed with competing binding partners. 
The BiCAP technique is adaptable to a wide array of downstream experimental assays, and the high degree of specificity afforded by this technique allows more nuanced investigations into the mechanics of protein complex assembly than is currently possible using standard affinity purification techniques.

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification BiCAP

This manuscript describes the protocol for Bimolecular Complementation Affinity Purification (BiCAP). This novel method facilitates the specific isolation and downstream proteomic characterization of any two interacting proteins, while excluding un-complexed individual proteins as well as complexes formed with competing binding partners.

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research ...