CK é suportado pelo programa de Pós-Graduação da Universidade Columbia. UB é membro da Leukemia and Lymphoma Society of America, o destinatário da New Investigator Award da Fundação de Pesquisa leucemia e é apoiado pela Columbia University New Faculdade start-up fundos.

1. Isolamento de Linfócitos B do baço e Estimulação <ol><li> Colher os baços de camundongos deficientes AID 12 entre 2-3 meses de idade. O isolamento do baço é realizada em condições estéreis e os órgãos mantidos temporariamente em soro fisiológico frio tampão fosfato (PBS) contendo 15% de soro fetal bovino (FBS). </li><li> O baço é então transferido para um capuz estéreis de cultura de tecidos e homogeneizado em 5 mL de PBS suplementado com FBS 2,5%. Transferir o homogeneizado para um tubo falcon 15 mL. </li><li> Centrifugar a amostra de tecido homogeneizado esplênica em 1000rpm por 10 minutos a 4 ° C para agregar as células. </li><li> Decantar o sobrenadante após a centrifugação. Ressuspender o pellet celular em 10 mL de glóbulos vermelhos (RBC) tampão de lise em temperatura ambiente por 7 minutos para evitar a contaminação por células vermelhas do sangue. </li><li> Centrífuga de amostra a 1000 rpm por 10 minutos e decantar o sobrenadante e ressuspender as células em 10 mL de PBS contendo 2,5% de SFB. </li><li> Remover 100 mL alíquota e contar as células em uma diluição 1:1000 utilizando um hemocitômetro padrão usando azul de tripano para excluir as células mortas. Aproximadamente 20-30 milhões de células pode ser obtido por baço. </li><li> Centrífuga de amostra em 1000rpm por 10 minutos e decantar o sobrenadante. </li><li> Ressuspender o sedimento em 0,5% BSA / PBS contendo 2mM EDTA, na concentração de 10 7 células por 90 mL. </li><li> Adicionar anti-CD43 revestidas de anticorpo esferas magnéticas para as células a se ligam especificamente não-B células. Use 10 gotas mL por 90 mL (10 7 células). Misturar bem e incubar a 4 ° C por 20 minutos. </li><li> Quando as células foram marcadas, lavá-los, adicionando 2,5% FBS / PBS para o topo do tubo. Centrífuga de amostra a 1000 rpm por 10 minutos. </li><li> Decantar o sobrenadante. Ressuspender as células em 0,1% BSA / PBS na concentração de 10x10 7 células por ml. </li><li> Montar uma coluna de classificação magnética em um separador magnético. Posição de um tubo cônico diretamente sob a coluna para coletar o fluxo através da coluna e carga com 3mL 0,5% BSA / PBS para preparar e lavar. </li><li> Uma vez que o fluido de lavagem tem fluído através, substitua-o por um tubo de nova coleção. Se a amostra é inferior a 1 mL, ajustar o volume da amostra a 1 mL com 0,5% BSA / PBS / EDTA e carregar a amostra na coluna. Coloque apenas um máximo mL de células por coluna e use várias colunas se necessário. </li><li> Permitir que as células passivamente o fluxo através da coluna e recolher as células não ligado no tubo cônico na coluna. Lavar a coluna 4 vezes com 3 mL de 0,5% BSA / PBS, continuando a recolher o escoamento. </li><li> Recolher todo o fluxo por meio em que CD43 negativo células B em repouso será enriquecido. Descartar a coluna. Centrífuga de fluxo contínuo a 1000 rpm por 10 minutos. </li><li> Drenar o sobrenadante e adicionar 10 mL de médio (15% FCS / + glutamina, Pen / Strep, não os aminoácidos essenciais, 50 mM Β-ME) </li><li> Contagem de células e cultura em 10 6 células por ml. </li><li> A fim de estimular o crescimento de células B e proliferação, complementar o meio com anticorpos recombinantes IL-4 e anti-CD40 de tal forma que a concentração final é de 20 mcg / mL e 1 mg / ml, respectivamente, e transferência das células para um balão cultura. </li><li> Cultura das células durante a noite. Contagem de células e diluir a 10 6 células por ml, acrescentando IL-4 e CD40, conforme apropriado. </li><li> Células de cultura por 72 horas antes da infecção viral. </li></ol> 2. Transfecção de células Produtor Utilizam protocolos estabelecidos para transfecção usando lipídios catiônicos ou fosfato de cálcio. 10 centímetros transfectar 3 placas por construir DNA, usando 100 mg de DNA plasmídeo por placa. Nós usam rotineiramente o método de transfecção de fosfato de cálcio 13, 14 e nota título viral alta, quando suplementados com cloroquina. <ol><li> Use 60% -70% de células confluentes Phoenix como células produtor a ser transfectadas. Neste contagem de células confluência deve ser de 5 milhões de células por 10 placa cm. </li><li> Uma hora antes da transfecção, substituir a mídia com nova mídia completo para Phoenix crescimento celular. </li><li> Em um tubo estéril eppendorpf, combine 100 mg de embalagens construir DNA, 250 L de CaCl 2 0,5 M, e ajustar o volume final de 500 mL com água estéril </li><li> Usando uma pipeta de 1 mL, vigorosamente mix esta solução com 500 mL 2X HNP em um tubo de polipropileno 15mL </li><li> Permitir essa mistura descansar em temperatura ambiente por 80-10 minutos. Durante esse tempo, um precipitado se formará. </li><li> Adicione a mistura de transfecção gota a gota, para as células enquanto agita o meio para distribuir a mistura por toda parte. </li><li> Incubar as células a 37 ° C por 12 horas. </li><li> 12 horas após a transfecção, substituir o meio com 8ml completa meio de crescimento de células B e as células voltem a 37 ° C incubadora. </li></ol> 3. Infecção de células B do baço Stimulated <ol><li> Remover o sobrenadante das células Phoenix 48hr pós-transfection e passar o sobrenadante através de um filtro de 0,2 mícron para remover quaisquer restos celulares. </li><li> Mix 3 mL de vírus contendo o sobrenadante com 3 mL de células pré-ativadas B (como no passo 1). A fim de melhorar a adsorção viral para as células, adicionar polibrene numa concentração final de 16 mg por mL. </li><li> Infectar as células por centrifugação a 2500 rpm por 90 minutos a 30 ° C. </li><li> Imediatamente após o spin, incubar por mais 48-72 horas a 37 ° C para permitir o crescimento e proliferação celular. </li></ol> 4. Análise de Citometria de Fluxo <ol><li> Usando um citômetro de fluxo, analisar as células para a expressão de superfície de IgG1 B220 e de superfície. A presença de IgG1 na superfície das células indica que a recombinação mudança de classe tem ocorrido como resultado de resgate bem sucedido através da complementação retroviral do gene AID. </li></ol> 5. Resultados representante Temos resgatado com sucesso a deficiência do fator de ativação da proteína Desaminase Citidina Induzida (AID) da AID-deficiente (AID-/ -) B-linfócitos usando transdução retroviral. Brevemente, geramos retrovírus recombinante expressando AID mouse (empregada) de proteína por transfecting células Phoenix com PMX-MAID-GFP 15-18. Os vírus colhidos foram infectadas em células-AID deficiente B obtidos AID camundongos deficientes em ex recombinação mudança de classe vivo (CSR) condições de estimulação 19. As células B infectadas foram então analisados ​​para a RSE para IgG1 após 72h em cultura através da análise de citometria de fluxo. A Figura 2 mostra a detecção de IgG1 na superfície de células B, com ajuda, mas não construir o vazio, indicando que a RSE tem ocorrido como resultado de resgate expressão AID. <img src="/files/ftp_upload/2371/2371fig1.jpg" alt="Figura 1" /> Figura 1: Esquema de embalagens retroviral no interior das células produtor: Gene de interesse, representada por Ψ, foi subclonado em PMX-IRES-GFP, como descrito anteriormente 15. O plasmídeo foi transfectado em uma linhagem de células viral embalagem ecotropic capaz de produzir gag-pol e proteína do envelope (Phoenix, Orbigen), utilizando o método de fosfato de cálcio 13, 14. Quarenta e oito horas após a transfecção, sobrenadante contendo partículas virais foi colhido para a infecção em células alvo principal B obtidas de camundongos. <img src="/files/ftp_upload/2371/2371fig2.jpg" alt="Figura 2" /> Figura 2: células AID deficiente B, estimuladas com anti-CD40 e IL-4 foram infectados com um retrovírus contendo PMX-MAID GFP ou um retrovírus expressando GFP sozinho. O nível da RSE para IgG1 foi avaliada através da análise FACS.

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Não há conflitos de interesse declarados.

Transdução retroviral de células B do baço, como descrito aqui e, conforme ilustrado na figura 1 é uma abordagem genética que é útil no estudo de linfócitos B, porque muitos dos eventos de desenvolvimento em lymphopoesis são controlados pela regulação da transcrição 1, 2. Nos estágios mais avançados da maturação das células B, provocando via CD40L é essencial para a indução de crescimento de células B, a entrada no ciclo celular, e proliferação de 11, 20. C...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
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		<tbody>
		
<tr>
<td>FCS</td>
<td>&nbsp;</td>
<td>Atlanta Biologicals</td>
<td>S11550</td>
<td>&nbsp;</td>
<tr>
<td>RPMI</td>
<td>&nbsp;</td>
<td>Invitrogen/Gibco</td>
<td>22400</td>
<td>&nbsp;</td>
<tr>
<td>PBS</td>
<td>&nbsp;</td>
<td>Invitrogen/Gibco</td>
<td>20012</td>
<td>&nbsp;</td>
<tr>
<td>Red Blood Cell (RBC) lysis buffer</td>
<td>&nbsp;</td>
<td>Sigma Aldrich</td>
<td>R7757</td>
<td>&nbsp;</td>
<tr>
<td>CD43 beads</td>
<td>&nbsp;</td>
<td>Miltenyi</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>B Cell Complete Media</td>
<td>&nbsp;</td>
<td>Various components</td>
<td>Various Components</td>
<td>RPMI, 15% FCS, 1% Non-Essential Amino Acids, 1% Sodium Pyruvate, 1% HEPES, 1% Pen-Strep, 50&mu;M &beta;-Mercaptoethanol</td>
</tr>
<tr>
<td>IL-4</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Anti-CD40</td>
<td>&nbsp;</td>
<td>BD Pharmigen</td>
<td>553787</td>
<td>&nbsp;</td>
<tr>
<td>polybrene</td>
<td>&nbsp;</td>
<td>Sigma Aldrich</td>
<td>107689 &#x2028;</td>
<td>&nbsp;</td>
<tr>
<td>Chloroquine diphosphate salt</td>
<td>&nbsp;</td>
<td>Sigma Aldrich</td>
<td>C6628</td>
<td>Used at 100mM</td>
</tr>
<tr>
<td>Phoenix Eco cells (Murine)</td>
<td>&nbsp;</td>
<td>Orbigen</td>
<td>RVC-10002</td>
<td>&nbsp;</td>
<tr>
<td>PE-Cy5-&alpha;-mouse-CD45R (B220)</td>
<td>&nbsp;</td>
<td>eBioscience</td>
<td>15-0452-81</td>
<td>&nbsp;</td>
<tr>
<td>PE-&alpha;-mouse-IgG1</td>
<td>&nbsp;</td>
<td>BD Pharmigen</td>
<td>A85-1</td>
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recombinant retroviral production and infection of b cells

A expressão de genes transgênicos em células eucarióticas é uma abordagem inversa poderosa genética em que um gene de interesse é expressa sob o controle de um sistema de expressão heteróloga para facilitar a análise do fenótipo resultante. Esta abordagem pode ser usada para expressar um gene que não é normalmente encontrado no organismo, para expressar uma forma mutante do gene de um produto, ou sobre-expressar uma forma dominante negativo do produto do gene. É particularmente útil no estudo do sistema hematopoético, onde a regulação da transcrição é um mecanismo de controle importante no desenvolvimento e diferenciação das células B 1, revisto em 2-4. Rato genética é uma ferramenta poderosa para o estudo dos genes humanos e doenças. Uma análise comparativa do mouse e do genoma humano revela conservação da sintenia em mais de 90% do genoma 5. Além disso, grande parte da tecnologia usada em modelos do rato é aplicável ao estudo dos genes humanos, por exemplo, interrupções e substituição de genes alelos 6 . No entanto, a criação de um camundongo transgênico requer uma grande quantidade de recursos de natureza financeira e técnica. Vários projetos já começaram a compilar bibliotecas de knock out linhagens de camundongos (KOMP, EUCOMM, NorCOMM) ou estirpes mutagênese induzida (RIKEN), que exigem esforços em larga escala e de colaboração 7. Portanto, é desejável para o primeiro estudo do fenótipo de um gene desejado em um modelo de cultura celular de células primárias antes de avançar para um modelo de mouse. Retroviral DNA se integra ao DNA do hospedeiro, de preferência dentro ou perto de unidades de transcrição ou ilhas CpG, resultando em estável e hereditária expressão do gene de interesse embalados, evitando silenciamento transcricional 8 9. Os genes são transcritos, em seguida, sob o controle de um promotor retroviral de alta eficiência, resultando em uma alta eficiência de transcrição e produção de proteína. Portanto, a expressão retroviral pode ser usado com células que são difíceis de transfecção, desde as células estão em um estado ativo durante a mitose. Porque os genes estruturais do vírus estão contidos dentro da linha de célula de embalagem, os vetores de expressão usada para clonar o gene de interesse não contêm genes estruturais do vírus, que tanto elimina a possibilidade de revertentes viral e aumenta a segurança de trabalhar com sobrenadantes viral como não virions infecciosos são produzidos 10. Aqui apresentamos um protocolo para a produção recombinante retroviral e subseqüente infecção de células B do baço. Após o isolamento, as células cultivadas esplênica são estimuladas com Th linfocinas derivadas e anti-CD40, o que induz a uma explosão de B proliferação e diferenciação celular 11. Este protocolo é ideal para o estudo de acontecimentos ocorridos no final B de desenvolvimento e diferenciação celular, como as células B são isolados do baço seguintes eventos iniciais hematopoéticas, mas antes da estimulação antigênica para induzir a diferenciação plasmocitária.

Watch this Scientific Journal Video about Recombinant Retroviral Production and Infection of B Cells at JoVE.com

Recombinant Retroviral Production and Infection of B Cells

Um sistema eficiente de estrutura e análise da função de um gene em um<em&gt; Ex vivo</em&gt; Cultura de linfócitos B do baço é descrito. Este método tira proveito da produção recombinante retroviral em uma linhagem de células helper livre, ecotrophic embalagem. Estável, hereditárias expressão de um gene de interesse dentro linfócitos primário é alcançado levando a geração de anticorpos de superfície de células B sofrer recombinação mudança de classe.

Produção recombinante Retroviral e infecção de células B

The transgenic expression of genes in eukaryotic cells is a powerful reverse genetic approach in which a gene of interest is expressed under the control ...

recombinant-retroviral-production-and-infection-of-b-cells

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Immunology and Infection

14.0K visualizações.  Columbia University College of Physicians and Surgeons. Um sistema eficiente de estrutura e análise da função de um gene em um Ex vivo Cultura de linfócitos B do baço é descrito. Este método tira proveito da produção recombinante retroviral em uma linhagem de células helper livre, ecotrophic embalagem. Estável, hereditárias expressão de um gene de interesse dentro linfócitos primário é alcançado levando a geração de anticorpos de superfície de células B sofrer recombinação mudança de clas...

Vídeo: Recombinant Retroviral Production and Infection of B Cells

Murine Model of CD40-activation of B cells

Research on B cells has shown that CD40 activation improves their antigen presentation capacity. When stimulated with interleukin-4 and CD40 ligand (CD40L), human B cells can be expanded without difficulties from small amounts of peripheral blood within 14 days to very large amounts of highly-pure CD40-B cells (&gt;109 cells per patient) from healthy donors as well as cancer patients1-4. CD40-B cells express important lymph node homing molecules and can attract T cells in vitro5. Furthermore they efficiently take up, process and present antigens to T cells6,7. CD40-B cells were shown to not only prime na&iacute;ve, but also expand memory T cells8,9. Therefore CD40-activated B cells (CD40-B cells) have been studied as an alternative source of immuno-stimulatory antigen-presenting cells (APC) for cell-based immunotherapy1,5,10. In order to further study whether CD40-B cells induce effective T cell responses in vivo and to study the underlying mechanism we established a cell culture system for the generation of murine CD40-activated B cells. Using splenocytes or purified B cells from C57BL/6 mice for CD40-activation, optimal conditions were identified as follows: Starting from splenocytes of C57BL/6 mice (haplotype H-2b) lymphocytes are purified by density gradient centrifugation and co-cultured with HeLa cells expressing recombinant murine CD40 ligand (tmuCD40L HeLa)11. Cells are recultured every 3-4 days and key components such as CD40L, interleukin-4, -Mercaptoethanol and cyclosporin A are replenished. In this protocol we demonstrate how to obtain fully activated murine CD40-B cells (mCD40B) with similar APC-phenotype to human CD40-B cells (Fig 1a,b). CD40-stimulation leads to a rapid outgrowth and expansion of highly pure (&gt;90%) CD19+ B cells within 14 days of cell culture (Fig 1c,d). To avoid contamination with non-transfected cells, expression of the murine CD40 ligand on the transfectants has to be controlled regularly (Fig 2). Murine CD40-activated B cells can be used to study B-cell activation and differentiation as well as to investigate their potential to function as APC in vitro and in vivo. Moreover, they represent a promising tool for establishing therapeutic or preventive vaccination against tumors and will help to answer questions regarding safety and immunogenicity of this approach12.

In this video, we demonstrate the procedure of CD40-activation and expansion of murine B cells from splenocytes of C57BL/6 mice, which can be used as a model antigen-presenting cell (APC) to study induction of immunity.

Modelo murino de CD40-ativação de células B

Research on B cells has shown that CD40 activation improves their antigen presentation capacity. When stimulated with interleukin-4 and CD40 ligand ...

Imunologia e Infecção

Retroviral Transduction of T-cell Receptors in Mouse T-cells

T-cell receptors (TCRs) play a central role in the immune system. TCRs on T-cell surfaces can specifically recognize peptide antigens presented by antigen presenting cells (APCs)1. This recognition leads to the activation of T-cells and a series of functional outcomes (e.g. cytokine production, killing of the target cells). Understanding the functional role of TCRs is critical to harness the power of the immune system to treat a variety of immunology related diseases (e.g. cancer or autoimmunity).
It is convenient to study TCRs in mouse models, which can be accomplished in several ways. Making TCR transgenic mouse models is costly and time-consuming and currently there are only a limited number of them available2-4. Alternatively, mice with antigen-specific T-cells can be generated by bone marrow chimera. This method also takes several weeks and requires expertise5. Retroviral transduction of TCRs into in vitro activated mouse T-cells is a quick and relatively easy method to obtain T-cells of desired peptide-MHC specificity. Antigen-specific T-cells can be generated in one week and used in any downstream applications. Studying transduced T-cells also has direct application to human immunotherapy, as adoptive transfer of human T-cells transduced with antigen-specific TCRs is an emerging strategy for cancer treatment6.
Here we present a protocol to retrovirally transduce TCRs into in vitro activated mouse T-cells. Both human and mouse TCR genes can be used. Retroviruses carrying specific TCR genes are generated and used to infect mouse T-cells activated with anti-CD3 and anti-CD28 antibodies. After in vitro expansion, transduced T-cells are analyzed by flow cytometry.

We present a protocol to produce antigen-specific mouse T-cells using retroviral transduction

Transdução retroviral de receptor de células T no rato células T

T-cell receptors (TCRs) play a central role in the immune system. TCRs on T-cell surfaces can specifically recognize peptide antigens presented by antigen ...

Production and Titering of Recombinant Adeno-associated Viral Vectors

In recent years recombinant adeno-associated viral vectors (AAV) have become increasingly valuable for in vivo studies in animals, and are also currently being tested in human clinical trials. Wild-type AAV is a non-pathogenic member of the parvoviridae family and inherently replication-deficient. The broad transduction profile, low immune response as well as the strong and persistent transgene expression achieved with these vectors has made them a popular and versatile tool for in vitro and in vivo gene delivery. rAAVs can be easily and cheaply produced in the laboratory and, based on their favourable safety profile, are generally given a low safety classification. Here, we describe a method for the production and titering of chimeric rAAVs containing the capsid proteins of both AAV1 and AAV2. The use of these so-called chimeric vectors combines the benefits of both parental serotypes such as high titres stocks (AAV1) and purification by affinity chromatography (AAV2). These AAV serotypes are the best studied of all AAV serotypes, and individually have a broad infectivity pattern. The chimeric vectors described here should have the infectious properties of AAV1 and AAV2 and can thus be expected to infect a large range of tissues, including neurons, skeletal muscle, pancreas, kidney among others. The method described here uses heparin column purification, a method believed to give a higher viral titer and cleaner viral preparation than other purification methods, such as centrifugation through a caesium chloride gradient. Additionally, we describe how these vectors can be quickly and easily titered to give accurate reading of the number of infectious particles produced.

Recombinant adeno-associated virus (rAAVs) vectors are becoming increasingly valuable for in vivo studies in animals. We describe how rAAVs can be produced in the laboratory and how these vectors can be titered to give an accurate reading of the number of infectious particles produced.

Produção e titulação de adeno-associados recombinantes Vetores Virais

In recent years recombinant adeno-associated viral vectors (AAV) have become increasingly valuable for in vivo studies in animals, and are also currently ...

Efficient Recombinant Parvovirus Production with the Help of Adenovirus-derived Systems

Rodent parvoviruses (PV) such as rat H-1PV and MVM, are small icosahedral, single stranded, DNA viruses. Their genome includes two promoters P4 and P38 which regulate the expression of non-structural (NS1 and NS2) and capsid proteins (VP1 and VP2) respectively1. They attract high interest as anticancer agents for their oncolytic and oncosuppressive abilities while being non-pathogenic for humans2. NS1 is the major effector of viral cytotoxicity3. In order to further enhance their natural antineoplastic activities, derivatives from these vectors have been generated by replacing the gene encoding for the capsid proteins with a therapeutic transgene (e.g. a cytotoxic polypeptide, cytokine, chemokine, tumour suppressor gene etc.)4. The recombinant parvoviruses (recPVs) vector retains the NS1/2 coding sequences and the PV genome telomeres which are necessary for viral DNA amplification and packaging. Production of recPVs occurs only in the producer cells (generally HEK293T), by co-transfecting the cells with a second vector (pCMV-VP) expressing the gene encoding for the VP proteins (Fig. 1)4. The recPV vectors generated in this way are replication defective. Although recPVs proved to possess enhanced oncotoxic activities with respect to the parental viruses from which they have been generated, their production remains a major challenge and strongly hampers the use of these agents in anti-cancer clinical applications.
We found that introduction of an Ad-5 derived vector containing the E2a, E4(orf6) and the VA RNA genes (e.g. pXX6 plasmid) into HEK293T improved the production of recPVs by more than 10 fold in comparison to other protocols in use. Based on this finding, we have constructed a novel Ad-VP-helper that contains the genomic adenoviral elements necessary to enhance recPVs production as well as the parvovirus VP gene unit5. The use of Ad-VP-helper, allows production of rec-PVs using a protocol that relies entirely on viral infection steps (as opposed to plasmid transfection), making possible the use of cell lines that are difficult to transfect (e.g. NB324K) (Fig. 2). We present a method that greatly improves the amount of recombinant virus produced, reducing both the production time and costs, without affecting the quality of the final product5. In addition, large scale production of recPV (in suspension cells and bioreactors) is now conceivable.

Here we describe a protocol based only on cell infection, which improves the efficiency of recombinant parvovirus production by more than 100 fold in comparison to other protocols in use. This protocol relies on the use of a novel adenovirus 5-based helper containing the parvovirus VP transcription unit (Ad-VP).

Produção Parvovirus eficiente recombinante com a ajuda de Adenovirus sistemas derivados

Rodent parvoviruses (PV) such as rat H-1PV and MVM, are small icosahedral, single stranded, DNA viruses. Their genome includes two promoters P4 and P38 ...

Detection of True IgE-expressing Mouse B Lineage Cells

B lymphocyte immunoglobulin heavy chain (IgH) class switch recombination (CSR) is a process wherein initially expressed IgM switches to other IgH isotypes, such as IgA, IgE and IgG. Measurement of IgH CSR in vitro is a key method for the study of a number of biologic processes ranging from DNA recombination and repair to aspects of molecular and cellular immunology. In vitro CSR assay involves the flow cytometric measurement surface Ig expression on activated B cells. While measurement of IgA and IgG subclasses is straightforward, measurement of IgE by this method is problematic due to soluble IgE binding to Fc&#949;RII/CD23 expressed on the surface of activated B cells. Here we describe a unique procedure for accurate measurement of IgE-producing mouse B cells that have undergone CSR in culture. The method is based on trypsin-mediated cleavage of IgE-CD23 complexes on cell surfaces, allowing for detection of IgE-producing B lineage cells by cytoplasmic staining. This procedure offers a convenient solution for flow cytometric analysis of CSR to IgE.

In vitro analysis of class switch recombination in mice is challenging due to cytophilic IgE molecules bound to Fc receptors on the surface of B cells. We describe a method for IgE detection using trypsin-mediated cleavage of surface-bound IgE prior to fixation and permeabilization for cytoplasmic fluorescence staining.

Detecção de True IgE-expressando Rato B células da linhagem

B lymphocyte immunoglobulin heavy chain (IgH) class switch recombination (CSR) is a process wherein initially expressed IgM switches to other IgH ...

Generation of Recombinant Human IgG Monoclonal Antibodies from Immortalized Sorted B Cells

Finding new methods for generating human monoclonal antibodies is an active research field that is important for both basic and applied sciences, including the development of immunotherapeutics. However, the techniques to identify and produce such antibodies tend to be arduous and sometimes the heavy and light chain pair of the antibodies are dissociated. Here, we describe a relatively simple, straightforward protocol to produce human recombinant monoclonal antibodies from human peripheral blood mononuclear cells using immortalization with Epstein-Barr Virus (EBV) and Toll-like receptor 9 activation. With an adequate staining, B cells producing antibodies can be isolated for subsequent immortalization and clonal expansion. The antibody transcripts produced by the immortalized B cell clones can be amplified by PCR, sequenced as corresponding heavy and light chain pairs and cloned into immunoglobulin expression vectors. The antibodies obtained with this technique can be powerful tools to study relevant human immune responses, including autoimmunity, and create the basis for new therapeutics.

Synthesis of human monoclonal antibodies is the first step in studies aimed at unraveling the pathophysiological mechanisms of auto-antibody-mediated immune responses. We have developed a protocol to generate recombinant human immunoglobulin G (IgG) monoclonal antibodies from blood sorted B cells, including B-cell isolation, antibody cloning and in vitro synthesis.

Geração de IgG Humana Recombinante de Anticorpos Monoclonais As células seleccionadas a partir de B imortalizadas

Finding new methods for generating human monoclonal antibodies is an active research field that is important for both basic and applied sciences, ...

Retroviral Transduction of Bone Marrow Progenitor Cells to Generate T-cell Receptor Retrogenic Mice

T cell receptor (TCR) signaling is essential in the development and differentiation of T cells in the thymus and periphery, respectively. The vast array of TCRs proves studying a specific antigenic response difficult. Therefore, TCR transgenic mice were made to study positive and negative selection in the thymus as well as peripheral T cell activation, proliferation and tolerance. However, relatively few TCR transgenic mice have been generated specific to any given antigen. Thus, studies involving TCRs of varying affinities for the same antigenic peptide have been lacking. The generation of a new TCR transgenic line can take six or more months. Additionally, any specific backcrosses can take an additional six months. In order to allow faster generation and screening of multiple TCRs, a protocol for retroviral transduction of bone marrow was established with stoichiometric expression of the TCR&#945; and TCR&#946; chains and the generation of retrogenic mice. Each retrogenic mouse is essentially a founder, virtually negating a founder effect, while the length of time to generate a TCR retrogenic is cut from six months to approximately six weeks. Here we present a rapid and flexible alternative to TCR transgenic mice that can be expressed on any chosen background with any particular TCR.

We present a rapid and flexible protocol for a single T cell receptor (TCR) retroviral-based in vivo expression system. Retroviral vectors are used to transduce bone marrow progenitor cells to study T cell development and function of a single TCR in vivo as an alternative to TCR transgenic mice.

Transdução retroviral de Células de Medula Óssea progenitoras para gerar células T Receptor Retrogenic Mice

T cell receptor (TCR) signaling is essential in the development and differentiation of T cells in the thymus and periphery, respectively.  The vast array ...

Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins

Stromal interaction molecule-1 (STIM1) is a type-I transmembrane protein located on the endoplasmic reticulum (ER) and plasma membranes (PM). ER-resident STIM1 regulates the activity of PM Orai1 channels in a process known as store operated calcium (Ca2+) entry which is the principal Ca2+ signaling process that drives the immune response. STIM1 undergoes post-translational N-glycosylation at two luminal Asn sites within the Ca2+ sensing domain of the molecule. However, the biochemical, biophysical, and structure biological effects of N-glycosylated STIM1 were poorly understood until recently due to an inability to readily obtain high levels of homogeneous N-glycosylated protein. Here, we describe the implementation of an in vitro chemical approach which attaches glucose moieties to specific protein sites applicable to understanding the underlying effects of N-glycosylation on protein structure and mechanism. Using solution nuclear magnetic resonance spectroscopy we assess both efficiency of the modification as well as the structural consequences of the glucose attachment with a single sample. This approach can readily be adapted to study the myriad glycosylated proteins found in nature.

Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins

Biochemical and structural analyses of glycosylated proteins require relatively large amounts of homogeneous samples. Here, we present an efficient chemical method for site-specific glycosylation of recombinant proteins purified from bacteria by targeting reactive Cys thiols.

Direcionamento de tióis cisteína para in Vitro site-specific glicosilação de proteínas recombinantes

Stromal interaction molecule-1 (STIM1) is a type-I transmembrane protein located on the endoplasmic reticulum (ER) and plasma membranes (PM). ER-resident ...

"Liver-on-a-Chip" Cultures of Primary Hepatocytes and Kupffer Cells for Hepatitis B Virus Infection

Despite the exceptional infectivity of the hepatitis B virus (HBV) in vivo, where only three viral genomes can result in a chronicity of experimentally infected chimpanzees, most in vitro models require several hundreds to thousands of viral genomes per cell in order to initiate a transient infection. Additionally, static 2D cultures of primary human hepatocytes (PHH) allow only short-term studies due to their rapid dedifferentiation. Here, we describe 3D liver-on-a-chip cultures of PHH, either in monocultures or in cocultures with other nonparenchymal liver-resident cells. These offer a significant improvement to studying long-term HBV infections with physiological host cell responses. In addition to facilitating drug efficacy studies, toxicological analysis, and investigations into pathogenesis, these microfluidic culture systems enable the evaluation of curative therapies for HBV infection aimed at eliminating covalently closed, circular (ccc)DNA. This presented method describes the set-up of PHH monocultures and PHH/Kupffer cell co-cultures, their infection with purified HBV, and the analysis of host responses. This method is particularly applicable to the evaluation of long-term effects of HBV infection, treatment combinations, and pathogenesis.

&quot;Liver-on-a-Chip&quot; Cultures of Primary Hepatocytes and Kupffer Cells for Hepatitis B Virus Infection

The goal of this protocol is to provide a step-by-step guide to perform 3-D &#34;liver-on-a-chip&#34; infection experiments with the hepatitis B virus.

"Fígado-on-a-Chip" culturas de hepatócitos primários e células de Kupffer para infecção pelo vírus da hepatite B

Despite the exceptional infectivity of the hepatitis B virus (HBV) in vivo, where only three viral genomes can result in a chronicity of experimentally ...

Retroviral Overexpression of CXCR4 on Murine B-1a Cells and Adoptive Transfer for Targeted B-1a Cell Migration to the Bone Marrow and IgM Production

As cell function is influenced by niche-specific factors in the cellular microenvironment, methods to dissect cell localization and migration can provide further insight on cell function. B-1a cells are a unique B cell subset in mice that produce protective natural IgM antibodies against oxidation-specific epitopes that arise during health and disease. B-1a cell IgM production differs depending on B-1a cell location, and therefore it becomes useful from a therapeutic standpoint to target B-1a localization to niches supportive of high antibody production. Here we describe a method to target B-1a cell migration to the bone marrow by retroviral-mediated overexpression of the C-X-C motif chemokine receptor 4 (CXCR4). Gene induction in primary murine B cells can be challenging and typically yields low transfection efficiencies of 10-20% depending on technique. Here we demonstrate that retroviral transduction of primary murine B-1a cells results in 30-40% transduction efficiency. This method utilizes adoptive cell transfer of transduced B-1a cells into B cell-deficient recipient mice so that donor B-1a cell migration and localization can be visualized. This protocol can be modified for other retroviral constructs and can be used in diverse functional assays post-adoptive transfer, including analysis of donor cell or host cell phenotype and function, or analysis of soluble factors secreted post B-1a cell transfer. The use of distinct donor and recipient mice differentiated by CD45.1 and CD45.2 allotype and the presence of a GFP reporter within the retroviral plasmid could also enable detection of donor cells in other, immune-sufficient mouse models containing endogenous B cell populations.

Here we describe a method for retroviral overexpression and adoptive transfer of murine B-1a cells to examine in vivo B-1a cell migration and localization. This protocol can be extended for diverse downstream functional assays including quantification of donor B-1a cell localization or analysis of donor cell-derived secreted factors post-adoptive transfer.

Superexpressão retroviral de CXCR4 em células Murine B-1a e transferência adotiva para migração de células B-1a direcionadas para a produção de medula óssea e igM

As cell function is influenced by niche-specific factors in the cellular microenvironment, methods to dissect cell localization and migration can provide ...