D.R.W. is supported by NIH grants AI089972 and AI113217, and by the Mucosal Immunology Studies Team, and holds a Career Award for Medical Scientists from the Burroughs Wellcome Fund.

NOTE: All experiments described here were in accordance with The Institutional Animal Care and Use Committee (IACUC) guidelines and approved by Animal Research Children&#8217;s Hospital (ARCH), Boston, Mass.
1. Preparation of Reagents
<ol>
	<li>1,000x IL-4 Stock: Dilute IL-4 cytokine to 20 &#181;g/ml in H2O or 0.1% bovine serum albumin (BSA). Dispense in 200 &#181;l aliquots to 1.5 ml microcentrifuge tubes and store at -20 &#176;C.</li>
	<li>1,000x anti-CD40: Obtain from the manufacturer at 1.0 mg/ml,...

<ol>
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R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reprogramming+IgH+isotype-switched+B+cells+to+functional-grade+induced+pluripotent+stem+cells.">Reprogramming IgH isotype-switched B cells to functional-grade induced pluripotent stem cells.</a> Proceedings of the National Academy of Sciences of the United States of America. 109 (34), 13745-13750 (2012).</li><li>Wesemann, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immature+B+cells+preferentially+switch+to+IgE+with+increased+direct+S&#181;+to+S&#949;+recombination.">Immature B cells preferentially switch to IgE with increased direct S&#181; to S&#949; recombination.</a> The Journal of experimental medicine. 208 (13), 2733-2746 (2011).</li><li>Zarrin, A. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+evolutionarily+conserved+target+motif+for+immunoglobulin+class-switch+recombination.">An evolutionarily conserved target motif for immunoglobulin class-switch recombination.</a> Nature immunology. 5, 1275-1281 (2004).</li><li>Fan, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+class-specific+polyclonal+antibody-based+indirect+competitive+ELISA+for+detecting+fluoroquinolone+residues+in+milk.">Development of a class-specific polyclonal antibody-based indirect competitive ELISA for detecting fluoroquinolone residues in milk.</a> Journal of Zhejiang University. Science. B. 13 (7), 545-554 (2012).</li><li>Perez, O., Krutzik, P., Nolan, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometric+analysis+of+kinase+signaling+cascades.">Flow cytometric analysis of kinase signaling cascades.</a> Methods in molecular biology (Clifton, N.J.). 263, 67-94 (2004).</li><li>Jamur, M., Oliver, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+fixatives+for+immunostaining.">Cell fixatives for immunostaining.</a> Methods in molecular biology (Clifton, N.J.). 588, 55-61 (2010).</li><li>Ishizaka, T., Ishizaka, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+passive+sensitization.+IV.+Dissociation+of+IgE+molecules+from+basophil+receptors+at+acid+pH.">Mechanisms of passive sensitization. IV. Dissociation of IgE molecules from basophil receptors at acid pH.</a> Journal of immunology (Baltimore, MD. : 1950). 112 (3), 1078-1084 (1950).</li><li>Erazo, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unique+Maturation+Program+of+the+IgE+Response+In+Vivo.">Unique Maturation Program of the IgE Response In Vivo.</a> Immunity. 26, 191-203 (2007).</li><li>Xiong, H., Dolpady, J., Wabl, M., Curotto de Lafaille, M. A., Lafaille, J. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+IgE(+)+B+cells+are+derived+from+T+cell-dependent+and+T+cell-independent+pathways.">Human IgE(+) B cells are derived from T cell-dependent and T cell-independent pathways.</a> The Journal of allergy and clinical immunology. , (2014).</li><li>He, J. -. 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The authors have no disclosures.

Stimulation of mouse splenic B cells in culture with anti-CD40 and IL-4 will simulate T helper type 2 (TH2) interactions, encouraging class switching to IgG1 and IgE5. B cells can be activated for CSR in the context of total splenocytes12 or as purified splenic B cells11. As noted in the protocol (step 2.3), B cell enrichment is optional, and is at the discretion of the experimenter to determine if it would beneficial. Positive magnetic separation of B cells using CD45R(B220)-l...

During immunoglobulin heavy chain (IgH) class switch recombination (CSR) in mice and humans, the IgH &#956; constant region exons (C&#956;) are deleted and replaced by one of several sets of downstream constant region exons (CHs) (e.g. C&#947;, C&#949;, and C&#945;), resulting in a switch from the production of IgM to the production of other Ig classes (e.g. IgG, IgE, or IgA). CSR occurs within switch (S) regions, which are 1-10 kb sequences located 5&#8217; to each set of CHs1. The Activation-Induced Cytidine Deaminase (AID) enzyme initiates CSR via cytidine deamination activity.
IgE is a key mediator of allergic disease2 and a greater understanding of how IgE is produced and regulated may open doors to new therapeutic approaches to atopic disease. In mice and humans, IgE is the most tightly regulated Ig isotype. IgE is normally detected at levels thousands of times less than other IgH isotypes3, but can be highly elevated in disease states4. However, CSR to IgE is incompletely understood. In vitro activation of B cells using IL-4 in combination with either anti-CD40 or LPS, induces CSR to both IgG1 and IgE5. Activated B cells express the low affinity IgE receptor Fc&#949;RII/CD232,6, which binds soluble IgE secreted in culture after CSR. Therefore when analyzing with flow cytometry, B cells with receptor-bound IgE stain similarly to B cells endogenously expressing IgE7. While it is known that mouse B cells express the low affinity IgG receptor Fc&#947;RIIB1 (CD32)8, in our experience it does not appear to interfere with measurement of class switching to IgG1. However, when measuring IgE switching after B cell activation in culture, nonspecific surface-bound IgE may obscure the analysis. With common staining methods, non-IgE-expressing cells stain positively for IgE.
Outlined here is a strategy that has been utilized to conduct CSR assays and detect true IgE-expressing B cells from mice9&#8211;11. Treatment of activated B cells with trypsin, a common lab reagent to digest protein, removes both cytophylic and membrane bound surface IgE. Subsequent permeabilization and staining for cytoplasmic IgE thus reveals the true IgE-producing cells.

<table border="0" cellpadding="0" cellspacing="0" width="958">
	<tbody>
		<tr height="37">
			<td height="37" style="height:37px;width:301px;">Name</td>
			<td style="width:179px;">Company</td>
			<td style="width:135px;">Catalog Number</td>
			<td style="width:343px;">Comments</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Anti-Mouse IgE FITC</td>
			<td>BD Pharmingen</td>
			<td>553415</td>
			<td>clone R35-72</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Rat Anti-Mouse IgG1 PE</td>
			<td>BD Pharmingen</td>
			<td>550083</td>
			<td>clone A85-1</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Methanol</td>
			<td>BDH</td>
			<td>BDH1135-4LP</td>
			<td>Keep at -20 &#176;C</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Falcon Cell Strainer 40 &#181;m Nylon</td>
			<td>Corning</td>
			<td>352340</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Falcon Cell Strainer 70 &#181;m Nylon</td>
			<td>Corning</td>
			<td>352350</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Anti-Hu/Mo CD45R(B220) PerCP-Cy5.5</td>
			<td>eBioscience</td>
			<td>45-4052-82</td>
			<td>clone RA3-6B2</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">anti-Mouse/Rat CD40</td>
			<td>eBioscience</td>
			<td>16-0402-85</td>
			<td>clone HM40-3</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">RPMI Medium 1640</td>
			<td>Gibco</td>
			<td>11875-093</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">HEPES (1M)</td>
			<td>Gibco</td>
			<td>15630-080</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">MEM-NEAA (100X)</td>
			<td>Gibco</td>
			<td>11140-050</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Phosphate Buffered Saline (10X)</td>
			<td>Lifetechnologies (Corning)</td>
			<td>46-013-CM</td>
			<td></td>
		</tr>
		<tr height="66">
			<td height="66" style="height:67px;">MACS CD45R (B220) microbeads&#160;</td>
			<td>Miltenyi Biotec</td>
			<td>130-049-501</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">MACS purification column</td>
			<td>Miltenyi Biotec</td>
			<td>130-042-401</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">IL-4</td>
			<td>PeproTech</td>
			<td>214-14</td>
			<td>Reconstitute in water or 0.1% BSA</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Formalin Solution, Neutral Buffered, 10%</td>
			<td>Sigma Aldrich</td>
			<td>HT501128-4L</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Trypsin-EDTA Solution (10X)</td>
			<td>Sigma Aldrich</td>
			<td>T4174-100mL</td>
			<td>5.0g Trypsin, 2.0g EDTA&#376;4Na per Liter of 0.9% NaCl</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Penicillin-Streptomycin</td>
			<td>Sigma Aldrich</td>
			<td>P0781-100mL</td>
			<td>10,000U Penicillin; 10 mg/mL Streptomycin (100X)</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">L-Glutamine 200mM</td>
			<td>Sigma Aldrich</td>
			<td>G7513</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">2-mercaptoethanol (99%)</td>
			<td>Sigma Aldrich</td>
			<td>M6250-100mL</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Red cell lysis buffer</td>
			<td>Sigma Aldrich</td>
			<td>R7757</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">Rat Anti-Mouse IgM RPE/cy7</td>
			<td>SouthernBiotech</td>
			<td>1140-17</td>
			<td>clone 1B4B1</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;">HyClone Fetal Calf Serum</td>
			<td>Thermo</td>
			<td>SH30910.03</td>
			<td></td>
		</tr>
		<tr height="161">
			<td height="161" style="height:161px;">B cell Stimulation media</td>
			<td></td>
			<td></td>
			<td style="width:343px;">B cell stimulation media consists of RPMI with fetal calf serum (15%), 20 mM HEPES, 1X MEM-NEAA, 2.0mM L-glutamine,&#160; 1X Penicillin-Streptomycin (Penicillin:100 U/ml, Streptomycin: 100 &#181;g/ml), Beta-mercaptoethanol (7 &#181;L/L), IL-4 (20 ng/mL), and anti-CD40 (1 &#181;g/mL)</td>
		</tr>
	</tbody>
</table>

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.

This procedure has been successfully implemented to study CSR to IgE in mouse B cells. To demonstrate the efficiency in measuring CSR, we stimulated mouse splenic B cells with anti-CD40 and IL-4 as described previously11. After five days of stimulation, cells were collected and processed using the protocol described above and stained with fluorescently-labeled IgM, IgG1, IgE, and B220 (CD45R) antibodies. Gated on the blasting lymphocytes (Figure 1), a clear population of IgE+ cells cannot be c...

Watch this Scientific Journal Video about Detection of True IgE-expressing Mouse B Lineage Cells at JoVE.com

Detection of True IgE-expressing Mouse B Lineage Cells

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.

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

detection-of-true-ige-expressing-mouse-b-lineage-cells

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Immunology and Infection

10.8K visualizações.  Brigham and Women's Hospital and Harvard Medical School. 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.