Este estudo foi financiado pelo National Institutes of Health (NIH) dos Estados Unidos (RO1 AI68002).

1. Recombinante SARS-CoV Preparação Protein RBD <ol><li> Prepare cálcio reagentes de transfecção de fosfato <ol><li> 2X tampão HBS preparação: Misture 16 g de NaCl, 0,4 g de Na 2 HPO 4 * 7H 2 O, e 13,0 g de HEPES. Ajustar o pH a 7,00 e educação de volume total para 1000 mL em água destilada. Depois de filtrar a solução para alíquota de esterilização, e armazená-lo a -20 ° C. Dica: Qualquer variação do valor de pH afetaria os resultados transfecção. Assim, é aconselhável testar vários valores de pH em torno de 7,00 (por exemplo, 6,99, 7,00, ou 7,01) e encontrar o melhor para a transfecção usando o método introduzido abaixo. </li><li> 2,5 M CaCl 2 preparação: Adicionar 73,5 g de CaCl 2 * 2H 2 O em água destilada em um volume final de 200 mL. Filtrar a solução e armazenar a -20 ° C. </li></ol></li><li> Transfecção do plasmídeo recombinante e proteína de purificação <ol><li> Dividir células 293T em 50-70% 24 h antes de confluência de transfecção. Cultivar células em T-175 cm 2 frascos de cultura de tecidos em 40 mL DMEM contendo 10% inativado pelo calor (HI) FBS e 1% Penicilina / Estreptomicina (P / S) a 37 ° C em 5% CO 2. </li><li> Todos os reagentes de transfecção deve ser trazido à temperatura ambiente antes de transfecção. Estes reagentes incluem 2X HBS, 2.5M CaCl 2, Dih 2 O, e rRBD 6 plasmídeo. Dica: O plasmídeo recombinante final de construção usado para a expressão da proteína deve conter um peptídeo sinal para garantir a secreção de proteínas recombinantes expressas para o sobrenadante da cultura. A tag Sua 6x pode ser adicionado ao C-terminal da proteína expressa para a purificação fácil. </li><li> Prepare uma mL 50 (A) e um 15 mL (B) BD tubo Falcon, e adicionar os reagentes aos tubos, como indicado na Tabela 1. Adicionar 2X tampão HBS para A. tubo no tubo B, adicionar 2,5 milhões de CaCl 2 e rRBD plasmídeo, e levar o volume para a exigência da Dih 2 O. <table border="1"><tbody><tr><td colspan="4"> A. Um T-175 cm 2 frasco de cultura de tecidos (4000 mL / frasco): preparar para a expressão rRBD </td></tr><tr><td colspan="2"> Um tubo </td><td colspan="2"> Tubo B </td></tr><tr><td> 2X HBS </td><td> 2000 mL </td><td> 2.5M CaCl 2 </td><td> 200 mL </td></tr><tr><td></td><td></td><td> DNA plasmídeo rRBD </td><td> 40 mcg </td></tr><tr><td></td><td></td><td> Dih 2 O para </td><td> 2000 mL </td></tr><tr><td colspan="4"> B. Um de 100 mm placa de Petri (1000 mL / prato): preparar-se para SARS produção pseudovirus </td></tr><tr><td colspan="2"> Um tubo </td><td colspan="2"> Tubo B </td></tr><tr><td> 2X HBS </td><td> 500 mL </td><td> 2.5M CaCl 2 </td><td> 50 mL </td></tr><tr><td></td><td></td><td> DNA plasmídeo SARS-CoV S </td><td> 5 mg </td></tr><tr><td></td><td></td><td> HIV-1 plasmídeo (pNL4-3.luc.RE) </td><td> 5 mg </td></tr><tr><td></td><td></td><td> Dih 2 O para </td><td> 500 mL </td></tr></tbody></table> Tabela 1. Preparação da mistura Transfection e volumes Os volumes listados na Tabela 1 são para uma unidade de transfecção. Se frascos mais ou pratos são utilizados para a transfecção, ajustar volumes em conformidade. </li><li> Adicionar a solução de DNA de cálcio no tubo B no tubo A de uma forma gota a gota, mantendo constante e suave a mistura em um vórtice. Deixe a mistura descansar em temperatura ambiente por 20-30 min. A chave para o sucesso de transfecção de fosfato de cálcio depende do tamanho e forma do precipitado formado. Assim, a mistura deve ser constantemente agitadas e, lentamente, para cumprir este requisito e, como conseqüência, melhorar a eficácia de transfecção. </li><li> Adicione a mistura de uma forma gotas e até mesmo em células 293T (4000 mL / frasco). Células de cultura em estufa a 37 ° C em 5% CO 2. </li><li> Substituir o meio de cultura com novas OPTI-MEM eu sem soro Médio Reduzido-Serum (50 mL / frasco) 8-10 h pós-transfecção. Continuar a células de cultura por mais dois dias na mesma condição. </li><li> Recolher o sobrenadante contendo proteínas expressas rRBD 72 h pós-transfecção. Centrifugar a 6000 rpm por 15 min para remover restos celulares. Adicionar coquetel inibidor de protease para o sobrenadante coletado e armazenar a 4 ° C durante a noite. </li><li> No dia seguinte, purificar proteínas recombinantes rRBD do sobrenadante da cultura através de instruções de Ni-NTA fabricante Superflow seguinte. </li><li> Concentre-se proteína purificada usando Amicon Ultra tubos concentração -15. Após a concentração de proteína,PBS adicionar aos tubos de concentração e centrifugar novamente para remover imidazol em tampão de eluição. Calcular a concentração de proteína e armazenar proteína purificada a -80 ° C até o uso. </li></ol></li></ol> 2. Imunização mouse e Coleta de Amostra <ol><li> Pré-aquecer Sigma sistema adjuvante (SAS) para 40-45 ° C de acordo com instruções do fabricante. Adicionar 1 mL de PBS por frasco e misturar bem. </li><li> Prepare a proteína adjuvante emulsão de acordo com o protocolo na Tabela 2. Pipeta calculada proteína rRBD em um tubo de 1,5 mL. Adicionar igual volume de adjuvante SAS para o tubo e vortex vigorosamente por 2-3 min para formar emulsão. Dica: Os volumes listados na Tabela 2 são para um mouse. Ajustar volumes de acordo com os números do mouse real usado. Para cada grupo, misture as proteínas e adjuvante necessários para cada vacina. Sempre preparar uma amostra suplementar para a vacinação para garantir a precisão. <table border="1"><tbody><tr><td> Grupo </td><td> 1 ª vacina (200 mL / rato) </td><td> 2 ª vacina (200 mL / rato) </td><td> 3 ª vacina (200 mL / rato) </td></tr><tr><td> proteína rRBD </td><td> 20 g de proteína em PBS (100 mL) + 100 mL SAS </td><td> 10 g de proteína em PBS (100 L) + 100 mL SAS </td><td> 10 g de proteína em PBS (100 L) + 100 mL SAS </td></tr><tr><td> PBS controle </td><td> 100 mL PBS + 100 mL SAS </td><td> 100 mL PBS + 100 mL SAS </td><td> 100 mL PBS + 100 mL SAS </td></tr></tbody></table> Tabela 2. Protocolo de imunização do rato </li><li> Por via subcutânea prime-imunizar fêmeas BALB / c (4-6 semanas de idade, cinco ratos / grupo), e aumentar duas vezes com rRBD e SAS, conforme indicado na Tabela 2. Use PBS grupo como o controle. O site para injeções subcutâneas geralmente escolhido é a pele solta entre as omoplatas. Alternativamente, o abdômen ventral é comumente usado, porque é mais fácil para injetar, e pode observar qualquer vazamento dos locais de injeção. Quando repetidas doses de vacinas são usadas, é fácil selecionar os locais de injeção diferentes, prevenindo potenciais reacções cutâneas locais. </li><li> Sangrar camundongos via retro-orbital com anestésico antes da imunização e 10 dias após cada vacinação, soros e calor a 56 ° C por 30 min para a inativação do complemento. Loja do mouse soros a -20 ° C até o uso. </li></ol> 3. Detecção de neutralização usando ensaio de neutralização Pseudovirus <ol><li> Prepare pseudovirus SARS <ol><li> Dividir células 293T em 100 milímetros de tecido placas de cultura de petri (2x10 6 células / prato) 16 h antes da transfecção, as células crescem e como acima. </li><li> Preparar reagentes de transfecção, conforme indicado na Tabela 1. Proteína co-transfecção um plasmídeo SARS-CoV S e um plasmídeo Env-defeituoso, luciferase expressando o genoma do HIV-1 (pNL4-3.luc.RE), utilizando reagentes de transfecção de cálcio fosfato. </li><li> Substituir médio com 10 mL fresco DMEM contendo 10% FBS e 1% P / S 10/08 h pós-transfecção. Recolher o sobrenadante contendo SARS pseudovirus 72 h pós-transfecção. </li><li> Pseudovirus filtro através de um filtro mM 0,45. Alíquotas e armazenar a -80 ° C até o uso. </li></ol></li><li> SARS ensaio de neutralização pseudovirus <ol><li> Dividir células 293T expressar SARS-CoV receptor ECA2 (ACE2/293T) a 10 4 cells/100 mL / poço em placas de 96 poços de cultura de tecido 16 h antes da infecção. </li><li> Diluir pseudovirus SARS por 2 vezes para detectar o título do vírus nas células ACE2/293T. </li><li> Serialmente diluída em soro de rato placas de 96 poços de cultura de tecidos, e adicionar igual volume de titulado pseudovirus SARS. Pré-incubação das placas a 37 ° C por 1 h. </li><li> Após a incubação, adicionar 100 mL da mistura de soros para as células-pseudovirus ACE2/293T, e continuam a crescer as células a 37 ° C em 5% CO 2. Adicionar nova DMEM 24 h mais tarde. </li><li> Remover completamente o sobrenadante da cultura de placas de 72 h pós-infecção. Adicionar 1X luciferase reagente de lise celular cultura (60 mL / poço), e promover a lise celular com constante agitação de placas por 1-2 h à temperatura ambiente. </li><li> Transferência de lisados ​​celulares (50 mL / poço) em placas luminômetro (Microfluor placas de 96 poços). Adicionar substrato luciferase (50 mL / poço), incluído no sistema de análise luciferase, e detectar a atividade luciferase relativa no luminômetro 384 Ultra. </li><li> Calcule SARS título de neutralização pseudovirus e presente como título de anticorpos neutralizantes 50% (NT 50) 6. </li></ol></li></ol>

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Não há conflitos de interesse declarados.

Densidade celular é um fator importante que afeta a eficácia de transfecção de cálcio à base de fosfato. Em nossa experiência, menos de 70% confluência das células traz os melhores resultados. Assim, a fim de melhorar a eficiência de transfecção, recomenda-se que a densidade de células ser mantidos a cerca de 50-70% de confluência. O cálcio método de transfecção de fosfato é geralmente pensado para ser menos eficiente em comparação com os métodos de transfecção outras, tais como a transfecção lipídica 16. No entanto, neste protocolo, foi utilizado um método modificado de cálcio fosfato de transfecção em que constante e lenta mistura da solução de transfecção em um vórtice garante a formação de um precipitado com o tamanho apropriado ea forma, melhorando assim a eficiência de transfecção.

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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>NaCl</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S7653</td>
<td>&nbsp;</td>
<tr>
<td>Na2HPO4*7H2O</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S2429</td>
<td>&nbsp;</td>
<tr>
<td>HEPES</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>H3375</td>
<td>&nbsp;</td>
<tr>
<td>CaCl2*2H2O</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>C5080</td>
<td>&nbsp;</td>
<tr>
<td>DMEM</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>12430</td>
<td>&nbsp;</td>
<tr>
<td>HI FBS</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>10438</td>
<td>&nbsp;</td>
<tr>
<td>Penicillin/Streptomycin</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15140</td>
<td>&nbsp;</td>
<tr>
<td>OPTI-MEM I Medium</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>31985</td>
<td>&nbsp;</td>
<tr>
<td>Protease inhibitor cocktail</td>
<td>&nbsp;</td>
<td>Roche</td>
<td>11836170001</td>
<td>&nbsp;</td>
<tr>
<td>Ni-NTA Superflow</td>
<td>&nbsp;</td>
<td>Qiagen</td>
<td>30450</td>
<td>&nbsp;</td>
<tr>
<td>Sigma adjuvant system</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>S6322</td>
<td>&nbsp;</td>
<tr>
<td>Luciferase assay system</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>E1501</td>
<td>&nbsp;</td>
<tr>
<td>Luciferase cell culture lysis reagent (5X)</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>E1531</td>
<td>&nbsp;</td>
<tr>
<td>Amicon Ultra - 15</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>UFC901024</td>
<td>&nbsp;</td>
<tr>
<td>Microfluor 96-well plates</td>
<td>&nbsp;</td>
<td>Thermo Scientific</td>
<td>7905</td>
<td>&nbsp;</td>
<tr>
<td>Ultra 384 luminometer</td>
<td>&nbsp;</td>
<td>Tecan Systems</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

protocol for recombinant rbd-based sars vaccines: protein preparation, animal vaccination and neutralization detection

Com base em seu perfil de segurança e capacidade de induzir potentes respostas imunes contra as infecções, as vacinas de subunidades têm sido usados ​​como candidatos para uma ampla variedade de patógenos 1-3. Desde que o sistema de células de mamíferos é capaz de modificação pós-traducional, formando proteínas adequadamente dobradas e glicosilada, proteínas recombinantes expressas em células de mamíferos têm demonstrado o maior potencial para manter elevada antigenicidade e imunogenicidade 4-6. Embora nenhum novo caso de SARS têm sido relatados desde 2004, futuros surtos são uma ameaça constante e, portanto, o desenvolvimento de vacinas contra a SARS-CoV é um passo prudente preventiva e deve ser realizada. O RBD de proteína SARS-CoV S desempenha um papel importante na ligação do receptor e indução de anticorpos neutralizantes específicos contra a infecção pelo vírus 7-9. Portanto, neste protocolo, descrevemos novos métodos para o desenvolvimento de uma vacina de subunidade RBD baseada contra SARS. Resumidamente, a proteína recombinante RBD (rRBD) foi expressa em sobrenadante de cultura de células de mamíferos 293T para obter uma proteína dobrado corretamente com conformação adequada e elevada imunogenicidade 6. A transfecção do plasmídeo recombinante codificação RBD às células foi então realizada usando um método de transfecção de fosfato de cálcio 6,10 com algumas modificações. Comparado com o método de transfecção lipídica 11,12, este método modificado de cálcio fosfato de transfecção é mais barato, mais fácil de manusear, e tem o potencial para alcançar alta eficácia, uma vez um complexo de transfecção com o tamanho e forma adequadas é formado 13,14. Finalmente, um ensaio de neutralização pseudovirus SARS foi introduzida no protocolo e usado para detectar a atividade neutralizante de soros de camundongos vacinados com a proteína rRBD. Este ensaio é relativamente seguro, não envolve um infecciosas SARS-CoV, e pode ser realizada sem a exigência de um laboratório de biossegurança-3 15. O protocolo aqui descrito também pode ser usado para desenhar e estudar vacinas subunidade recombinante contra outros vírus com proteínas de classe I de fusão, por exemplo, HIV, vírus sincicial respiratório (VSR), o vírus Ebola, o vírus influenza, bem como Nipah e Handra. Além disso, os métodos para gerar um pseudovirus e, posteriormente, estabelecer um ensaio de neutralização pseudovirus pode ser aplicada a todos estes vírus.

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Protocol for Recombinant RBD-based SARS Vaccines: Protein Preparation, Animal Vaccination and Neutralization Detection

Este protocolo descreve um procedimento geral para o estudo de ligação aos receptores recombinantes de domínio (RBD) com base em vacinas de subunidade contra a SARS. Ele inclui métodos para transfecção e expressão da proteína em células RBD 293T, a imunização de camundongos com RBD e detecção de atividade de neutralização dos soros do mouse usando um ensaio de neutralização estabelecida SARS pseudovirus.

Protocolo para vacinas recombinantes RBD baseado SARS: Preparação de proteínas, Vacinação Animal e Detecção de Neutralização

Based on their safety profile and ability to induce potent immune responses against infections, subunit vaccines have been used as candidates for a wide ...

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JoVE Journal

Immunology and Infection

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Vídeo: Protocol for Recombinant RBD-based SARS Vaccines: Protein Preparation, Animal Vaccination and Neutralization Detection

Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce

This protocol describes a simple approach for adhesive-tape-based sampling of tomato and other fresh produce surfaces, followed by on-tape fluorescence in situ hybridization (FISH) for rapid culture-independent detection of Salmonella spp. Cell-charged tapes can also be placed face-down on selective agar for solid-phase enrichment prior to detection. Alternatively, low-volume liquid enrichments (liquid surface miniculture) can be performed on the surface of the tape in non-selective broth, followed by FISH and analysis via flow cytometry. To begin, sterile adhesive tape is brought into contact with fresh produce, gentle pressure is applied, and the tape is removed, physically extracting microbes present on these surfaces. Tapes are mounted sticky-side up onto glass microscope slides and the sampled cells are fixed with 10% formalin (30 min) and dehydrated using a graded ethanol series (50, 80, and 95%; 3 min each concentration). Next, cell-charged tapes are spotted with buffer containing a Salmonella-targeted DNA probe cocktail and hybridized for 15 - 30 min at 55&deg;C, followed by a brief rinse in a washing buffer to remove unbound probe. Adherent, FISH-labeled cells are then counterstained with the DNA dye 4',6-diamidino-2-phenylindole (DAPI) and results are viewed using fluorescence microscopy. For solid-phase enrichment, cell-charged tapes are placed face-down on a suitable selective agar surface and incubated to allow in situ growth of Salmonella microcolonies, followed by FISH and microscopy as described above. For liquid surface miniculture, cell-charged tapes are placed sticky side up and a silicone perfusion chamber is applied so that the tape and microscope slide form the bottom of a water-tight chamber into which a small volume (&le; 500 &mu;L) of Trypticase Soy Broth (TSB) is introduced. The inlet ports are sealed and the chambers are incubated at 35 - 37&deg;C, allowing growth-based amplification of tape-extracted microbes. Following incubation, inlet ports are unsealed, cells are detached and mixed with vigorous back and forth pipetting, harvested via centrifugation and fixed in 10% neutral buffered formalin. Finally, samples are hybridized and examined via flow cytometry to reveal the presence of Salmonella spp. As described here, our "tape-FISH" approach can provide simple and rapid sampling and detection of Salmonella on tomato surfaces. We have also used this approach for sampling other types of fresh produce, including spinach and jalape&ntilde;o peppers.

Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce

This protocol describes a simple adhesive-tape-based approach for sampling of tomato and other fresh produce surfaces, followed by rapid whole cell detection of Salmonella using fluorescence in situ hybridization (FISH).

Combinação de adesivos de fita baseada em amostragem e de fluorescência In situ Hibridação para detecção rápida de Salmonella On Fresh Produce

This protocol describes a simple approach for adhesive-tape-based sampling of tomato and other fresh produce surfaces, followed by on-tape fluorescence in ...

Imunologia e Infecção

Whole-animal Imaging and Flow Cytometric Techniques for Analysis of Antigen-specific CD8+ T Cell Responses after Nanoparticle Vaccination

Traditional vaccine adjuvants, such as alum, elicit suboptimal CD8+ T cell responses. To address this major challenge in vaccine development, various nanoparticle systems have been engineered to mimic features of pathogens to improve antigen delivery to draining lymph nodes and increase antigen uptake by antigen-presenting cells, leading to new vaccine formulations optimized for induction of antigen-specific CD8+ T cell responses. In this article, we describe the synthesis of a &#8220;pathogen-mimicking&#8221; nanoparticle system, termed interbilayer-crosslinked multilamellar vesicles (ICMVs) that can serve as an effective vaccine carrier for co-delivery of subunit antigens and immunostimulatory agents and elicitation of potent cytotoxic CD8+ T lymphocyte (CTL) responses. We describe methods for characterizing hydrodynamic size and surface charge of vaccine nanoparticles with dynamic light scattering and zeta potential analyzer and present a confocal microscopy-based procedure to analyze nanoparticle-mediated antigen delivery to draining lymph nodes. Furthermore, we show a new bioluminescence whole-animal imaging technique utilizing adoptive transfer of luciferase-expressing, antigen-specific CD8+ T cells into recipient mice, followed by nanoparticle vaccination, which permits non-invasive interrogation of expansion and trafficking patterns of CTLs in real time. We also describe tetramer staining and flow cytometric analysis of peripheral blood mononuclear cells for longitudinal quantification of endogenous T cell responses in mice vaccinated with nanoparticles.

We describe whole-animal imaging and flow cytometry-based techniques for monitoring expansion of antigen-specific CD8+ T cells in response to immunization with nanoparticles in a murine model of vaccination.

Imaginologia todo animal e técnicas de citometria de fluxo para CD8 + respostas de células T Análise do antigénio específico da Nanoparticle após vacinação

Traditional vaccine adjuvants, such as alum, elicit suboptimal CD8+ T cell responses. To address this major challenge in vaccine development, various ...

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

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

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

A administração intranasal de recombinantes Vacinas contra Influenza em quimérico rato Modelos para estudar a imunidade mucosal

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

In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model

Current methodologies for antigen-specific killing are limited to in vitro use or utilized in infectious disease models. However, there is not a protocol specifically intended to measure antigen-specific killing without an infection. This protocol is designed and describes methods to overcome these limitations by allowing for the detection of antigen-specific killing of a target cell by CD8+ T cells in vivo. This is accomplished by merging a vaccination model with a traditional CFSE-labeled target killing assay. This combination allows the researcher to assess the antigen-specific CTL potential directly and quickly as the assay is not dependent upon tumor growth or infection. In addition, the readout is based on flow cytometry and so should be readily accessible to most researchers. The major limitation of the study is identifying the timeline in vivo that is appropriate to the hypothesis being tested. Variations in antigen strength and mutations in the T cells that may result in differential cytolytic function need to be carefully assessed to determine the optimal time for cell harvest and assessment. The appropriate concentration of peptide for vaccination has been optimized for hgp10025-33 and OVA257-264, but further validation would be needed for other peptides that may be more appropriate to a given study. Overall, this protocol allows a quick assessment of killing function in vivo and can be adapted to any given antigen.

In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model

The goal of this protocol is to allow for detection of in vivo antigen-specific killing of a target cell in a murine model.

Na Vivo Ensaio para detecção de células T antígeno-específicas função citolítica usando um modelo de vacinação

Current methodologies for antigen-specific killing are limited to in vitro use or utilized in infectious disease models. However, there is not a protocol ...

Generating Recombinant Avian Herpesvirus Vectors with CRISPR/Cas9 Gene Editing

Herpesvirus of turkeys (HVT) is an ideal viral vector for the generation of recombinant vaccines against a number of avian diseases, such as avian influenza (AI), Newcastle disease (ND), and infectious bursal disease (IBD), using bacterial artificial chromosome (BAC) mutagenesis or conventional recombination methods. The clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 system has been successfully used in many settings for gene editing, including the manipulation of several large DNA virus genomes. We have developed a rapid and efficient CRISPR/Cas9-mediated genome editing pipeline to generate recombinant HVT. To maximize the potential use of this method, we present here detailed information about the methodology of generating recombinant HVT expressing the VP2 protein of IBDV. The VP2 expression cassette is inserted into the HVT genome via an NHEJ (nonhomologous end-joining)-dependent repair pathway. A green fluorescence protein (GFP) expression cassette is first attached to the insert for easy visualization and then removed via the Cre-LoxP system. This approach offers an efficient way to introduce other viral antigens into the HVT genome for the rapid development of recombinant vaccines.

Herpesvirus of turkeys (HVT) is widely used as a vector platform for the generation of recombinant vaccines against a number of avian diseases. This article describes a simple and rapid approach for the generation of recombinant HVT-vectored vaccines using an integrated NHEJ-CRISPR/Cas9 and Cre-Lox system.

Geração de vetores recombinantes Herpesvirus aviária com CRISPR/Cas9 Gene edição

Herpesvirus of turkeys (HVT) is an ideal viral vector for the generation of recombinant vaccines against a number of avian diseases, such as avian ...

Analysis of Iophenoxic Acid Analogues in Small Indian Mongoose (Herpestes Auropunctatus) Sera for Use as an Oral Rabies Vaccination Biological Marker

The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases reported annually. The control of RABV circulation in wildlife reservoirs is typically accomplished by a strategy of oral rabies vaccination (ORV). Currently no wildlife ORV program exists in Puerto Rico. Research into oral rabies vaccines and various bait types for mongooses has been conducted with promising results. Monitoring the success of ORV relies on estimating bait uptake by target species, which typically involves evaluating a change in RABV neutralizing antibodies (RVNA) post vaccination. This strategy may be difficult to interpret in areas with an active wildlife ORV program or in areas where RABV is enzootic and background levels of RVNA are present in reservoir species. In such situations, a biomarker incorporated with the vaccine or the bait matrix may be useful. We offered 16 captive mongooses placebo ORV baits containing ethyl-iophenoxic acid (et-IPA) in concentrations of 0.4% and 1% inside the bait and 0.14% in the external bait matrix. We also offered 12 captive mongooses ORV baits containing methyl-iophenoxic acid (me-IPA) in concentrations of 0.035%, 0.07% and 0.14% in the external bait matrix. We collected a serum sample prior to bait offering and then weekly for up to eight weeks post offering. We extracted Iophenoxic acids from sera into acetonitrile and quantified using liquid chromatography/mass spectrometry. We analyzed sera for et-IPA or me-IPA by liquid chromatography-mass spectrometry. We found adequate marking ability for at least eight and four weeks for et- and me-IPA, respectively. Both IPA derivatives could be suitable for field evaluation of ORV bait uptake in mongooses. Due to the longevity of the marker in mongoose sera, care must be taken to not confound results by using the same IPA derivative during consecutive evaluations.

Analysis of Iophenoxic Acid Analogues in Small Indian Mongoose Herpestes Auropunctatus Sera for Use as an Oral Rabies Vaccination Biological Marker

We offered captive mongooses placebo oral rabies vaccine baits with ethyl or methyl iophenoxic acid as a biomarker and verified bait uptake using a novel liquid chromatography with tandem mass spectrometry (LC-MS/MS) method.

Análise de análogos de ácido Iofenoxico em pequeno mangusto indiano (Herpestes auropunctatus) sera para uso como um marcador biológico de vacinação contra a raiva oral

The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases ...

A Rapid, Multiplex Dual Reporter IgG and IgM SARS-CoV-2 Neutralization Assay for a Multiplexed Bead-Based Flow Analysis System

The COVID-19 pandemic has underscored the need for rapid high-throughput methods for sensitive and specific serological detection of infection with novel pathogens, such as SARS-CoV-2. Multiplex serological testing can be particularly useful because it can simultaneously analyze antibodies to multiple antigens that optimizes pathogen coverage, and controls for variability in the organism and the individual host response. Here we describe a SARS-CoV-2 IgG 3-plex fluorescent microsphere-based assay that can detect both IgM and IgG antibodies to three major SARS-CoV-2 antigens-the spike (S) protein, spike angiotensin-converting enzyme-2 (ACE2) receptor-binding domain (RBD), and nucleocapsid (Nc). The assay was shown to have comparable performance to a SARS-CoV-2 reference assay for IgG in serum obtained at &#8805;21 days from symptom onset but had higher sensitivity with samples collected at &#8804;5 days from symptom onset. Further, using soluble ACE2 in a neutralization assay format, inhibition of antibody binding was demonstrated for S and RBD.

A flow analysis system for bead-based multiplexed assays which provides a two-reporter readout was used for the development of multiplex serological and antibody neutralization assays that can simultaneously measure neutralizing IgG and IgM antibodies for SARS-CoV-2.

Um teste de neutralização rápido e multiplex dual reporter IgG e IgM SARS-CoV-2 para um sistema de análise de fluxo baseado em contas multiplexadas

The COVID-19 pandemic has underscored the need for rapid high-throughput methods for sensitive and specific serological detection of infection with novel ...

Detection of SARS-CoV-2 Receptor-Binding Domain Antibody using a HiBiT-Based Bioreporter

The emergence of the COVID-19 pandemic has increased the need for better serological detection methods to determine the epidemiologic impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The increasing number of SARS-CoV-2 infections raises the need for better antibody detection assays. Current antibody detection methods compromise sensitivity for speed or are sensitive but time-consuming. A large proportion of SARS-CoV-2-neutralizing antibodies target the receptor-binding domain (RBD), one of the primary immunogenic compartments of SARS-CoV-2. We have recently designed and developed a highly sensitive, bioluminescent-tagged RBD (NanoLuc HiBiT-RBD) to detect SARS-CoV-2 antibodies. The following text describes the procedure to produce the HiBiT-RBD complex and a fast assay to evaluate the presence of RBD-targeting antibodies using this tool. Due to the durability of the HiBiT-RBD protein product over a wide range of temperatures and the shorter experimental procedure that can be completed within 1 h, the protocol can be considered as a more efficient alternative to detect SARS-CoV-2 antibodies in patient serum samples.

The outlined protocol describes the procedure for producing the HiBiT-receptor-binding domain protein complex and its application for fast and sensitive detection of SARS-CoV-2 antibodies.

Detecção de anticorpo de domínio de ligação receptor sars-cov-2 usando um biorelato de domínio baseado em HiBiT

The emergence of the COVID-19 pandemic has increased the need for better serological detection methods to determine the epidemiologic impact of severe ...

Live Imaging and Quantification of Viral Infection in K18 hACE2 Transgenic Mice Using Reporter-Expressing Recombinant SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic has been caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, SARS-CoV-2 has been responsible for over 242 million infections and more than 4.9 million deaths worldwide. Similar to other viruses, studying SARS-CoV-2 requires the use of experimental methods to detect the presence of virus in infected cells and/or in animal models. To overcome this limitation, we generated replication-competent recombinant (r)SARS-CoV-2 that expresses bioluminescent (nanoluciferase, Nluc) or fluorescent (Venus) proteins. These reporter-expressing rSARS-CoV-2 allow tracking viral infections in vitro and in vivo based on the expression of Nluc and Venus reporter genes. Here the study describes the use of rSARS-CoV-2/Nluc and rSARS-CoV-2/Venus to detect and track SARS-CoV-2 infection in the previously described K18 human angiotensin-converting enzyme 2 (hACE2) transgenic mouse model of infection using in vivo imaging systems (IVIS). This rSARS-CoV-2/Nluc and rSARS-CoV-2/Venus show rSARS-CoV-2/WT-like pathogenicity and viral replication in vivo. Importantly, Nluc and Venus expression allow us to directly track viral infections in vivo and ex vivo, in infected mice. These rSARS-CoV-2/Nluc and rSARS-CoV-2/Venus represent an excellent option to study the biology of SARS-CoV-2 in vivo, to understand viral infection and associated COVID-19 disease, and to identify effective prophylactic and/or therapeutic treatments to combat SARS-CoV-2 infection.

This protocol describes the dynamics of viral infections using luciferase- and fluorescence-expressing recombinant (r)SARS-CoV-2 and an in vivo imaging systems (IVIS) in K18 hACE2 transgenic mice to overcome the need of secondary approaches required to study SARS-CoV-2 infections in vivo.

Imagem ao vivo e quantificação da infecção viral em K18 hACE2 Camundongos transgênicos usando o recombinante SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic has been caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, SARS-CoV-2 has ...

Detection of Neutralization-sensitive Epitopes in Antigens Displayed on Virus-Like Particle (VLP)-Based Vaccines Using a Capture Assay

The virus-like particle (VLP) capture assay is an immunoprecipitation method, commonly known as a &#39;pull-down assay&#39; used to purify and isolate antigen-displaying VLPs. Surface antigen-specific antibodies are coupled to, and thus immobilized on a solid and insoluble matrix such as beads. Due to their high affinity to the target antigen, these antibodies can capture VLPs decorated with the cognate antigen anchored in the membrane envelope of the VLPs. This protocol describes the binding of antigen-specific antibodies to protein A- or G-conjugated magnetic beads. In our study, human immunodeficiency virus (HIV)-derived VLPs formed by the group-specific antigen (Gag) viral core precursor protein p55 Gag and displaying the envelope glycoproteins (Env) of HIV are examined. The VLPs are captured utilizing broadly neutralizing antibodies (bNAbs) directed against neutralization-sensitive epitopes in Env. The VLP capture assay outlined here represents a sensitive and easy-to-perform method to demonstrate that (i) the VLPs are decorated with the respective target antigen, (ii) the surface antigen retained its structural integrity as demonstrated by the epitope-specific binding of bNAbs used in the assay and (iii) the structural integrity of the VLPs revealed by the detection of Gag proteins in a subsequent Western blot-analysis. Consequently, the utilization of bNAbs for immunoprecipitation facilitates a prediction of whether VLP vaccines will be able to elicit a neutralizing B cell response in vaccinated humans. We anticipate that this protocol will furnish other researchers with a valuable and straightforward experimental approach to examine potential VLP-based vaccines.

Detection of Neutralization-sensitive Epitopes in Antigens Displayed on Virus-Like Particle VLP-Based Vaccines Using a Capture Assay

Here, we present a protocol to detect neutralization epitopes on antigen-displaying virus-like particles (VLPs). Immunoprecipitation of the human immunodeficiency virus (HIV)-derived VLPs is performed using envelope glycoproteins-specific monoclonal antibodies coupled to protein G-conjugated magnetic beads. Captured VLPs are subsequently subjected to SDS-PAGE and Western blot-analysis employing viral core protein Gag-specific antibodies.

Detecção de epítopos sensíveis à neutralização em antígenos exibidos em vacinas baseadas em partículas semelhantes a vírus (VLP) usando um ensaio de captura

The virus-like particle (VLP) capture assay is an immunoprecipitation method, commonly known as a &#39;pull-down assay&#39; used to purify and isolate ...