Name: development of cell-type specific anti-hiv gp120 aptamers for sirna delivery
Uploaded: 2011-06-23T12:00:00
Description: Watch this Scientific Journal Video about Development of Cell-type specific anti-HIV gp120 aptamers for siRNA delivery at JoVE.com

We thank Britta Hoehn, Guihua Sun, Harris Soifer and Lisa Scherer for helpful discussions. This work was supported by grants from the National Institutes of Health AI29329 and HL07470 awarded to J.J.R. The following reagents were obtained through the NIH AIDS Research and Reference Reagent Program, Division of AIDS, NIAID, NIH: The CHO-EE and CHO-gp160 cell line; the pNL4-3 luc vector; HIV-1BaL gp120 from DAIDS, NIAID.

1. Preparation of the RNA library
<ol>
<li>The starting DNA library contained 50 nucleotides of random sequences and was synthesized by Integrated DNA Technologies (Coralville, Iowa). The single stranded DNA oligo library sequence is 5'- GGG AGG ACG ATG CGG - N50- CAG ACG ACT CGC CCG A - 3' (81 nt). The random region is flanked by constant regions, which include the T7 promoter for in vitro transcription and a 3' tag for RT-PCR. The 5' and 3' constant sequences are 5' &#x2013; TAA TAC GAC TCA CTA TA...

<ol>
	<li>Tuerk, C., Gold, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+evolution+of+ligands+by+exponential+enrichment:+RNA+ligands+to+bacteriophage+T4+DNA+polymerase.">Systematic evolution of ligands by exponential enrichment: RNA ligands to bacteriophage T4 DNA polymerase.</a> Science. 249, 505-510 (1990).</li><li>Ellington, A. D., Szostak, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+selection+of+RNA+molecules+that+bind+specific+ligands.">In vitro selection of RNA molecules that bind specific ligands.</a> Nature. 346, 818-822 (1990).</li><li>Robertson, D. L., Joyce, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selection+in+vitro+of+an+RNA+enzyme+that+specifically+cleaves+single-stranded+DNA.">Selection in vitro of an RNA enzyme that specifically cleaves single-stranded DNA.</a> Nature. 344, 467-468 (1990).</li><li>Fitzwater, T., Polisky, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+SELEX+primer.">A SELEX primer.</a> Methods Enzymol. 267, 275-301 (1996).</li><li>Weiss, C. D., White, J. M. <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+stable+Chinese+hamster+ovary+cells+expressing+wild-type,+secreted,+and+glycosylphosphatidylinositol-anchored+human+immunodeficiency+virus+type+1+envelope+glycoprotein.">Characterization of stable Chinese hamster ovary cells expressing wild-type, secreted, and glycosylphosphatidylinositol-anchored human immunodeficiency virus type 1 envelope glycoprotein.</a> J Virol. 67, 7060-706 (1993).</li><li>Vodicka, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Indicator+cell+lines+for+detection+of+primary+strains+of+human+and+simian+immunodeficiency+viruses.">Indicator cell lines for detection of primary strains of human and simian immunodeficiency viruses.</a> Virology. 233, 193-198> (1997).</li><li>Zhou, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selection,+characterization+and+application+of+new+RNA+HIV+gp+120+aptamers+for+facile+delivery+of+Dicer+substrate+siRNAs+into+HIV+infected+cells.">Selection, characterization and application of new RNA HIV gp 120 aptamers for facile delivery of Dicer substrate siRNAs into HIV infected cells.</a> Nucleic Acids Res. , (2009).</li><li>Mayer, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chemical+biology+of+aptamers.">The chemical biology of aptamers.</a> Angew Chem Int Ed Engl. 48, 2672-2689 (2009).</li><li>Famulok, M., Hartig, J. S., Mayer, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+aptamers+and+aptazymes+in+biotechnology,+diagnostics,+and+therapy.">Functional aptamers and aptazymes in biotechnology, diagnostics, and therapy.</a> Chem Rev. 107, 3715-3743 (2007).</li><li>Chu, T. C., Twu, K. Y., Ellington, A. D., Levy, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aptamer+mediated+siRNA+delivery.">Aptamer mediated siRNA delivery.</a> Nucleic Acids Res. 34, e73-e73 (2006).</li><li>McNamara, J. O., 2nd, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+type-specific+delivery+of+siRNAs+with+aptamer-siRNA+chimeras.">Cell type-specific delivery of siRNAs with aptamer-siRNA chimeras.</a> Nat Biotechnol. 24, 1005-1015 (2006).</li><li>Dassie, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systemic+administration+of+optimized+aptamer-siRNA+chimeras+promotes+regression+of+PSMA-expressing+tumors.">Systemic administration of optimized aptamer-siRNA chimeras promotes regression of PSMA-expressing tumors.</a> Nat Biotechnol. 27, 839-849 (2009).</li><li>Zhou, J., Rossi, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+therapeutic+potential+of+cell-internalizing+aptamers.">The therapeutic potential of cell-internalizing aptamers.</a> Curr Top Med Chem. 9, 1144-1157 (2009).</li><li>Zhou, J., Li, H., Li, S., Zaia, J., Rossi, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+dual+inhibitory+function+aptamer-siRNA+delivery+system+for+HIV-1+therapy.">Novel dual inhibitory function aptamer-siRNA delivery system for HIV-1 therapy.</a> Mol Ther. 16, 1481-1489 (2008).</li></ol>

Aptamers are in vitro evolved nucleic acids that assume specific and stable three-dimensional shapes, thereby providing highly specific, tight binding to targeted molecules8. The low nanomolar binding affinity and exquisite specificity of aptamers to their targets make them versatile tools for diagnostics, in vivo imaging, and therapeutics9. With the advent of aptamer technology for targeted siRNA delivery it is now feasible to use the aptamer binding function for receptor mediated...

<table border="1">
	<tbody>
		<tr>
			<th>Name of the reagent</th>
			<th>Company</th>
			<th>Catalogue number</th>
			<th>Comments (optional)</th>
		</tr>
		<tr>
			<td>MF-Millipore membrane filter</td>
			<td>Millipore</td>
			<td>HAWP01300</td>
			<td>Pore size 0.45 &mu;m</td>
		</tr>
		<tr>
			<td>Swinnex Filter holder</td>
			<td>Millipore</td>
			<td>SX0001300</td>
			<td>13 mm diameter</td>
		</tr>
		<tr>
			<td>QIAquick Gel Extraction Kit</td>
			<td>QIAGEN</td>
			<td>28706</td>
			<td>DNA purification</td>
		</tr>
		<tr>
			<td>Microcon YM-30 column</td>
			<td>Millipore</td>
			<td>42410</td>
			<td>RNA concentration</td>
		</tr>
		<tr>
			<td>Bio-spin 30 column</td>
			<td>Bio-Rad</td>
			<td>732-6250</td>
			<td>RNA purification</td>
		</tr>
		<tr>
			<td>Taq PCR DNA polymerase</td>
			<td>Sigma-Aldrich</td>
			<td>D1806</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>ThermoScript RT-PCR system</td>
			<td>Invitrogen</td>
			<td>11146-024 </td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>DuraScribe T7 transcription Kit</td>
			<td>EpiCentre</td>
			<td>DS010925</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>dNTP for PCR</td>
			<td>Roche</td>
			<td>1 581 295</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ribonucleic acid, transfer from E.coli</td>
			<td>Sigma-Aldrich</td>
			<td>R1753</td>
			<td>tRNA competitor</td>
		</tr>
		<tr>
			<td>HIV-1Ba-L gp120 protein</td>
			<td>the AIDS Research and Reference Reagent Program</td>
			<td>4961</td>
			<td>Target protein</td>
		</tr>
		<tr>
			<td>Silencer siRNA labeling kit - Cy3</td>
			<td>Ambion</td>
			<td>1632</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Acid phenol/chloroform 5/1 solution (pH 4.5)</td>
			<td>Ambion</td>
			<td>AM9720</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Chloroform/Isopropanol 24/1 solution</td>
			<td>Sigma</td>
			<td>C0549</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Calf intestinal phosphatase (CIP)</td>
			<td>New England BioLab</td>
			<td>M0290L</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>T4 polynucleotide kinase</td>
			<td>New England BioLab</td>
			<td>M0201L</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Glycogen</td>
			<td>Roche</td>
			<td>10 901 393 001</td>
			<td>RNA precipitation</td>
		</tr>
		<tr>
			<td>Gamma-P32-ATP</td>
			<td>MP Biomedical</td>
			<td>013502002</td>
			<td>Radiactivity</td>
		</tr>
		<tr>
			<td>40% AccuGel 19:1</td>
			<td>National Diagnostics</td>
			<td>EC-850</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>10xTBE</td>
			<td>National Diagnostics</td>
			<td>EC-860</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>N,N,N,N'-Tetramethylethylenediamine (TMEMD)</td>
			<td>Sigma-Aldrich</td>
			<td>T9281</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ammonium persulfate (APS)</td>
			<td>Sigma-Aldrich</td>
			<td>A3678</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>L-methioine sulfoximine</td>
			<td>Sigma-Aldrich</td>
			<td>M5379-250 mg</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>RPMI Media 1640</td>
			<td>Invitrogen</td>
			<td>11835-030</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate solution, 7.5% w/v</td>
			<td>Invitrogen</td>
			<td>25080-094</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Minimum Essential Medium (MEM) (10&#xF0B4;)</td>
			<td>Invitrogen</td>
			<td>11430-030</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>MEM non-essential amino acid (100&#xF0B4;)</td>
			<td>Invitrogen</td>
			<td>11140-050</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>TA cloning kit with pCR 2.1 </td>
			<td>Invitrogen</td>
			<td>K2040-01</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

development of cell-type specific anti-hiv gp120 aptamers for sirna delivery

The global epidemic of infection by HIV has created an urgent need for new classes of antiretroviral agents. The potent ability of small interfering (si)RNAs to inhibit the expression of complementary RNA transcripts is being exploited as a new class of therapeutics for a variety of diseases including HIV. Many previous reports have shown that novel RNAi-based anti-HIV/AIDS therapeutic strategies have considerable promise; however, a key obstacle to the successful therapeutic application and clinical translation of siRNAs is efficient delivery. Particularly, considering the safety and efficacy of RNAi-based therapeutics, it is highly desirable to develop a targeted intracellular siRNA delivery approach to specific cell populations or tissues. The HIV-1 gp120 protein, a glycoprotein envelope on the surface of HIV-1, plays an important role in viral entry into CD4 cells. The interaction of gp120 and CD4 that triggers HIV-1 entry and initiates cell fusion has been validated as a clinically relevant anti-viral strategy for drug discovery. 
Herein, we firstly discuss the selection and identification of 2'-F modified anti-HIV gp120 RNA aptamers. Using a conventional nitrocellulose filter SELEX method, several new aptamers with nanomolar affinity were isolated from a 50 random nt RNA library. In order to successfully obtain bound species with higher affinity, the selection stringency is carefully controlled by adjusting the conditions. The selected aptamers can specifically bind and be rapidly internalized into cells expressing the HIV-1 envelope protein. Additionally, the aptamers alone can neutralize HIV-1 infectivity. Based upon the best aptamer A-1, we also create a novel dual inhibitory function anti-gp120 aptamer-siRNA chimera in which both the aptamer and the siRNA portions have potent anti-HIV activities. Further, we utilize the gp120 aptamer-siRNA chimeras for cell-type specific delivery of the siRNA into HIV-1 infected cells. This dual function chimera shows considerable potential for combining various nucleic acid therapeutic agents (aptamer and siRNA) in suppressing HIV-1 infection, making the aptamer-siRNA chimeras attractive therapeutic candidates for patients failing highly active antiretroviral therapy (HAART).

Watch this Scientific Journal Video about Development of Cell-type specific anti-HIV gp120 aptamers for siRNA delivery at JoVE.com

Development of Cell-type specific anti-HIV gp120 aptamers for siRNA delivery

Several 2&#x2019;-Fluoro RNA aptamers against HIV-1Ba-L gp120 with nanomole affinity are isolated from a RNA library by in vitro SELEX procedure. A new dual inhibitory function anti-gp120 aptamer-siRNA chimera is created and shows considerable promise for systemic anti-HIV therapy.

The global epidemic of infection by HIV has created an urgent need for new classes of antiretroviral agents. The potent ability of small interfering ...

development-cell-type-specific-anti-hiv-gp120-aptamers-for-sirna

Research

JoVE Journal

Immunology and Infection

Development of a Negative Selectable Marker for Entamoeba histolytica

Entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. The molecular techniques that have enabled the up- and down-regulation of gene expression rely on the transfection of stably maintained plasmids. While these have increased our understanding of Entamoeba virulence factors, the capacity to integrate exogenous DNA into genome, which would allow reverse genetics experiments, would be a significant advantage in the study of this parasite. The challenges presented by this organism include inability to select for homologous recombination events and difficulty to cure episomal plasmid DNA from transfected trophozoites. The later results in a high background of exogenous DNA, a major problem in the identification of trophozoites in which a bona fide genomic integration event has occurred. We report the development of a negative selection system based upon transgenic expression of a yeast cytosine deaminase and uracil phosphoribosyl transferase chimera (FCU1) and selection with prodrug 5-fluorocytosine (5-FC). The FCU1 enzyme converts non-toxic 5-FC into toxic 5-fluorouracil and 5-fluorouridine-5'-monophosphate. E. histolytica lines expressing FCU1 were found to be 30 fold more sensitive to the prodrug compared to the control strain.

Development of a Negative Selectable Marker for Entamoeba histolytica

We report development of a negative selection system in E. histolytica based upon transgenic expression of a chimeric protein (FCU1) and selection with the prodrug 5-fluorocytosine. The FCU1 protein is a fusion of yeast cytosine deaminase and uracil phosphoribosyltransferase. Expression of FCU1 resulted in increased E. histolytica sensitivity towards 5-fluorocytosine.

Entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. The molecular techniques that have enabled the ...

Peptide:MHC Tetramer-based Enrichment of Epitope-specific T cells

A basic necessity for researchers studying adaptive immunity with in vivo experimental models is an ability to identify T cells based on their T cell antigen receptor (TCR) specificity. Many indirect methods are available in which a bulk population of T cells is stimulated in vitro with a specific antigen and epitope-specific T cells are identified through the measurement of a functional response such as proliferation, cytokine production, or expression of activation markers1. However, these methods only identify epitope-specific T cells exhibiting one of many possible functions, and they are not sensitive enough to detect epitope-specific T cells at naive precursor frequencies. A popular alternative is the TCR transgenic adoptive transfer model, in which monoclonal T cells from a TCR transgenic mouse are seeded into histocompatible hosts to create a large precursor population of epitope-specific T cells that can be easily tracked with the use of a congenic marker antibody2,3. While powerful, this method suffers from experimental artifacts associated with the unphysiological frequency of T cells with specificity for a single epitope4,5. Moreover, this system cannot be used to investigate the functional heterogeneity of epitope-specific T cell clones within a polyclonal population.
	The ideal way to study adaptive immunity should involve the direct detection of epitope-specific T cells from the endogenous T cell repertoire using a method that distinguishes TCR specificity solely by its binding to cognate peptide:MHC (pMHC) complexes. The use of pMHC tetramers and flow cytometry accomplishes this6, but is limited to the detection of high frequency populations of epitope-specific T cells only found following antigen-induced clonal expansion. In this protocol, we describe a method that coordinates the use of pMHC tetramers and magnetic cell enrichment technology to enable detection of extremely low frequency epitope-specific T cells from mouse lymphoid tissues3,7. With this technique, one can comprehensively track entire epitope-specific populations of endogenous T cells in mice at all stages of the immune response.

This protocol describes the use of peptide:MHC tetramers and magnetic microbeads to isolate low frequency populations of epitope-specific T cells and analyze them by flow cytometry. This method enables the direct study of endogenous T cell populations of interest from in vivo experimental systems.

A  basic necessity for researchers studying adaptive immunity with in vivo experimental models is an  ability to identify T cells based on their T cell ...

Development of an IFN-&#947; ELISpot Assay to Assess Varicella-Zoster Virus-specific Cell-mediated Immunity Following Umbilical Cord Blood Transplantation

Varicella zoster virus (VZV) is a significant cause of morbidity and mortality following umbilical cord blood transplantation (UCBT). For this reason, antiherpetic prophylaxis is administrated systematically to pediatric UCBT recipients to prevent complications associated with VZV infection, but there is no strong, evidence based consensus that defines its optimal duration. Because T cell mediated immunity is responsible for the control of VZV infection, assessing the reconstitution of VZV specific T cell responses following UCBT could provide indications as to whether prophylaxis should be maintained or can be discontinued. To this end, a VZV specific gamma interferon (IFN-&#947;) enzyme-linked immunospot (ELISpot) assay was developed to characterize IFN-&#947; production by T lymphocytes in response to in vitro stimulation with irradiated live attenuated VZV vaccine. This assay provides a rapid, reproducible and sensitive measurement of VZV specific cell mediated immunity suitable for monitoring the reconstitution of VZV specific immunity in a clinical setting and assessing immune responsiveness to VZV antigens. &#160;

Development of an IFN-&amp;#947; ELISpot Assay to Assess Varicella-Zoster Virus-specific Cell-mediated Immunity Following Umbilical Cord Blood Transplantation

Novel generations of functional assays such as gamma interferon (IFN-&#947;) ELISpot, which detect cytokine production at the single cell level and provide both quantitative and qualitative characterization of T cell responses can be used to assess cell-mediated immune responses directed against varicella zoster virus (VZV).

Varicella zoster virus (VZV) is a significant cause of morbidity and mortality following umbilical cord blood transplantation (UCBT). For this reason, ...

Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a replicative niche. A cohort of effectors are translocated through this system into the host cell to manipulate host processes and allow the establishment of a unique lysosome-derived vacuole for replication. The method presented here involves the combination of two well-established techniques: specific gene silencing using siRNA and measurement of effector translocation using a FRET-based substrate that relies on &#946;-lactamase activity. Applying these two approaches, we can begin to understand the role of host factors in bacterial secretion system function and effector translocation. In this study we examined the role of Rab5A and Rab7A, both important regulators of the endocytic trafficking pathway. We demonstrate that silencing the expression of either protein results in a decrease in effector translocation efficiency. These methods can be easily modified to examine other intracellular and extracellular pathogens that also utilize secretion systems. In this way, a global picture of host factors involved in bacterial effector translocation may be revealed.

Applying Fluorescence Resonance Energy Transfer FRET to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Investigating the interactions between bacterial pathogens and their hosts is an important area of biological research. Here, we describe the necessary techniques to measure effector translocation by Coxiella burnetii during siRNA gene silencing using BlaM substrate.

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a ...

Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species

Foodborne infections in the US caused by Vibrio species have shown an upward trend. In the genus Vibrio, V. parahaemolyticus is responsible for the majority of Vibrio-associated infections. Thus, accurate differentiation among Vibrio spp. and detection of V. parahaemolyticus is critically important to ensure the safety of our food supply. Although molecular techniques are increasingly common, culture-depending methods are still routinely done and they are considered standard methods in certain circumstances. Hence, a novel chromogenic agar medium was tested with the goal of providing a better method for isolation and differentiation of clinically relevant Vibrio spp. The protocol compared the sensitivity, specificity and detection limit for the detection of V. parahaemolyticus between the new chromogenic medium and a conventional medium. Various V. parahaemolyticus strains (n=22) representing diverse serotypes and source of origins were used. They were previously identified by Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC), and further verified in our laboratory by tlh-PCR. In at least four separate trials, these strains were inoculated on the chromogenic agar and thiosulfate-citrate-bile salts-sucrose (TCBS) agar, which is the recommended medium for culturing this species, followed by incubation at 35-37 &#176;C for 24-96 hr. Three V. parahaemolyticus strains (13.6%) did not grow optimally on TCBS, nonetheless exhibited green colonies if there was growth. Two strains (9.1%) did not yield the expected cyan colonies on the chromogenic agar. Non-V. parahaemolyticus strains (n=32) were also tested to determine the specificity of the chromogenic agar. Among these strains, 31 did not grow or exhibited other colony morphologies. The mean recovery of V. parahaemolyticus on the chromogenic agar was ~96.4% relative to tryptic soy agar supplemented with 2% NaCl. In conclusion, the new chromogenic agar is an effective medium to detect V. parahaemolyticus and to differentiate it from other vibrios.

Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species

Detection and isolation of clinically relevant Vibrio species require selective and differential culture media. This study evaluated the ability of a new chromogenic medium to detect and identify V. parahaemolyticus and other related species. The new medium was found to have better sensitivity and specificity than the conventional medium.

Foodborne infections in the US caused by Vibrio species have shown an upward trend. In the genus Vibrio, V. parahaemolyticus is responsible for the ...

Development of Stem Cell-derived Antigen-specific Regulatory T Cells Against Autoimmunity

Autoimmune diseases arise due to the loss of immunological self-tolerance. Regulatory T cells (Tregs) are important mediators of immunologic self-tolerance. Tregs represent about 5 - 10% of the mature CD4+ T cell subpopulation in mice and humans, with about 1 - 2% of those Tregs circulating in the peripheral blood. Induced pluripotent stem cells (iPSCs) can be differentiated into functional Tregs, which have a potential to be used for cell-based therapies of autoimmune diseases. Here, we present a method to develop antigen (Ag)-specific Tregs from iPSCs (i.e., iPSC-Tregs). The method is based on incorporating the transcription factor FoxP3 and an Ag-specific T cell receptor (TCR) into iPSCs and then differentiating on OP9 stromal cells expressing Notch ligands delta-like (DL) 1 and DL4. Following in vitro differentiation, the iPSC-Tregs express CD4, CD8, CD3, CD25, FoxP3, and Ag-specific TCR and are able to respond to Ag stimulation. This method has been successfully applied to cell-based therapy of autoimmune arthritis in a murine model. Adoptive transfer of these Ag-specific iPSC-Tregs into Ag-induced arthritis (AIA)-bearing mice has the ability to reduce joint inflammation and swelling and to prevent bone loss.

We present here a method to develop functional antigen (Ag)-specific regulatory T cells (Tregs) from induced pluripotent stem cells (iPSCs) for immunotherapy of autoimmune arthritis in a murine model.

Autoimmune diseases arise due to the loss of immunological self-tolerance. Regulatory T cells (Tregs) are important mediators of immunologic ...

Development of an Economical DNA Delivery System by "Acufection" and its Application to Skin Research

Dysregulation of immune response in skin is associated with numerous human skin disorders. Direct transfer of immune-related genes into skin tissue is a fascinating approach to investigate immune modulation of cutaneous inflammation in mouse models of human diseases. Here we present a cost-effective protocol that delivered naked DNA in mouse skin and leads to transgene expression. The method is coined &#34;acufection&#34;, denoting acupuncture-mediated DNA transfection. To perform acufection, mouse skin was first infused with DNA in phosphate-buffered saline (PBS) and then pricked lightly with a bundle of acupuncture needles to facilitate the absorption of DNA and transfection into cells. The plasmid DNA is presumably taken up by the keratinocyte and dendritic cells (DCs) in the skin and expressed into protein. Mechanical prick with the needles per se did not cause skin damage or induce keratinocyte activation. The expression of the transfected genes was detected in the skin at both transcriptional and translational levels following acufection for 2 days and maintained up to 7 days. The primary goal for the development of this acufection method was to investigate a previously undefined isoform of IL-15. Using this method, an alternatively spliced IL-15 isoform with partially deleted exon 7 (IL-15&#916;E7) was expressed in the skin and subsequently treated with a Toll-like receptor 7 (TLR7) agonist, imiquimod (IMQ), to induce inflammation. Acufection-delivered IL-15&#916;E7 in skin suppressed keratinocyte proliferation, epidermal thickness and neutrophil recruitment in IMQ-induced cutaneous inflammation. With increasing interest in identifying the regulatory mechanisms of cutaneous inflammation, the protocol described here provides a cost effective and versatile alternative to the gene gun system or microseeding for DNA delivery in vivo. It may potentially allow discovery of the function of a novel gene in the skin or for investigating new treatment for cutaneous diseases.

Development of an Economical DNA Delivery System by &quot;Acufection&quot; and its Application to Skin Research

This protocol is a cost-effective alternative for expressing naked plasmid DNA in mouse skin. The overall goal of the protocol is to deliver immune-related genes into skin tissue to delineate the functional role of a specific gene in cutaneous inflammation.

Dysregulation of immune response in skin is associated with numerous human skin disorders. Direct transfer of immune-related genes into skin tissue is a ...

Zika Virus Specific Diagnostic Epitope Discovery

High-density peptide microarrays allow screening of more than six thousand peptides on a single standard microscopy slide. This method can be applied for drug discovery, therapeutic target identification, and developing of diagnostics. Here, we present a protocol to discover specific Zika virus (ZIKV) diagnostic peptides using a high-density peptide microarray. A human serum sample validated for ZIKV infection was incubated with a high-density peptide microarray containing the entire ZIKV protein translated into 3,423 unique 15 linear amino acid (aa) residues with a 14-aa residue overlap printed in duplicate. Staining with different secondary antibodies within the same array, we detected peptides that bind to Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibodies present in serum. These peptides were selected for further validation experiments. In this protocol, we describe the strategy followed to design, process, and analyze a high-density peptide microarray.

In this protocol, we describe a technique to discover Zika virus specific diagnostic peptides using a high-density peptide microarray. This protocol can readly be adapted for other emerging infectious diseases.

High-density peptide microarrays allow screening of more than six thousand peptides on a single standard microscopy slide. This method can be applied for ...

Quantitative PCR of T7 Bacteriophage from Biopanning

This protocol describes the use of quantitative PCR (qPCR) to enumerate T7 phages from phage selection experiments (i.e., &#34;biopanning&#34;). qPCR is a fluorescence-based approach to quantify DNA, and here, it is adapted to quantify phage genomes as a proxy for phage particles. In this protocol, a facile phage DNA preparation method is described using high-temperature heating without additional DNA purification. The method only needs small volumes of heat-treated phages and small volumes of the qPCR reaction. qPCR is high-throughput and fast, able to process and obtain data from a 96-well plate of reactions in 2&#8211;4 h. Compared to other phage enumeration approaches, qPCR is more time-efficient. Here, qPCR is used to enumerate T7 phages identified from biopanning against in vitro cystic fibrosis-like mucus model. The qPCR method can be extended to quantify T7 phages from other experiments, including other types of biopanning (e.g.,&#160;immobilized protein binding, in vivo phage screening) and other sources (e.g., water systems or body fluids). In summary, this protocol can be modified to quantify any DNA-encapsulated viruses.

A reproducible, accurate, and time efficient quantitative PCR (qPCR) method to enumerate T7 bacteriophage is described here. The protocol clearly describes phage genomic DNA preparation, PCR reaction preparation, qPCR cycling conditions, and qPCR data analysis.

This protocol describes the use of quantitative PCR (qPCR) to enumerate T7 phages from phage selection experiments (i.e., &#34;biopanning&#34;). qPCR is a ...

Antigenic Liposomes for Generation of Disease-specific Antibodies

Antibody responses provide critical protective immunity to a wide array of pathogens. There remains a high interest in generating robust antibodies for vaccination as well as understand how pathogenic antibody responses develop in allergies and autoimmune disease. Generating robust antigen-specific antibody responses is not always trivial. In mouse models, it often requires multiple rounds of immunizations with adjuvant that leads to a great deal of variability in the levels of induced antibodies. One example is in mouse models of peanut allergies where more robust and reproducible models that minimize mouse numbers and the use of adjuvant would be beneficial. Presented here is a highly reproducible mouse model of peanut allergy anaphylaxis. This new model relies on two key factors: (1) antigen-specific splenocytes are adoptively transferred from a peanut-sensitized mouse into a na&#239;ve recipient mouse, normalizing the number of antigen-specific memory B- and T-cells across a large number of mice; and (2) recipient mice are subsequently boosted with a strong multivalent immunogen in the form of liposomal nanoparticles displaying the major peanut allergen (Ara h 2). The major advantage of this model is its reproducibility, which ultimately lowers the number of animals used in each study, while minimizing the number of animals receiving multiple injections of adjuvant. The modular assembly of these immunogenic liposomes provides relatively facile adaptability to other allergic or autoimmune models that involve pathogenic antibodies.

Described is the preparation of antigenic liposomal nanoparticles and their use in stimulating B-cell activation in vitro and in vivo. Consistent and robust antibody responses led to the development of a new peanut allergy model. The protocol for generating antigenic liposomes can be extended to different antigens and immunization models.

Antibody responses provide critical protective immunity to a wide array of pathogens. There remains a high interest in generating robust antibodies for ...