Sign In

A subscription to JoVE is required to view this content. Sign in or start your free trial.

In This Article

  • Summary
  • Abstract
  • Introduction
  • Protocol
  • Representative Results
  • Discussion
  • Acknowledgements
  • Materials
  • References
  • Reprints and Permissions

Summary

Here we report a protocol for the quantification and differentiation of myocardial B-lymphocytes based on their location in the intravascular or endothelial space using flow cytometry.

Abstract

A growing body of evidence shows that B-lymphocytes play an important role in the context of myocardial physiology and myocardial adaptation to injury. However, the literature reports contrasting data on the prevalence of myocardial B-cells. B-cells have been reported to be both among the most prevalent immune cells in the rodent heart or to be present, but at a markedly lower prevalence than myeloid cells, or to be quite rare. Similarly, several groups have described that the number of myocardial B-cells increases after acute ischemic myocardial injury, but one group reported no changes in the number of B-cells of the injured myocardium. Implementation of a shared, reproducible method to assess the prevalence of myocardial B-cells is critical to harmonize observations from different research groups and thus promote the advancement of the study of B-cell myocardial interactions. Based on our experience, the seemingly contrasting observations reported in the literature likely stem from the fact that murine myocardial B-cells are mostly intravascular and connected to the microvascular endothelium. Therefore, the number of B-cells recovered from a murine heart is exquisitely sensitive to the perfusion conditions used to clean the organ and to the method of digestion used. Here we report an optimized protocol that accounts for these two critical variables in a specific way. This protocol empowers reproducible, flow cytometry-based analysis of the number of murine myocardial B-cells and allows researchers to distinguish extravascular vs. intravascular myocardial B-cells.

Introduction

B-lymphocytes are highly specialized immune cells that play an important role in both adaptive and innate immune responses1. There are two main populations of B-cells: a smaller population of B1 cells that are mostly produced during embryonic life, and a preponderant population of B2 cells that are produced in adult life in the bone marrow1. After maturing in the bone marrow, B-cells migrate to primary and secondary lymphoid organs. From there they continuously recirculate between lymphoid organs traveling through blood vessels and lymphatic vessels2. B-cells express specific antibodies on their s....

Protocol

All experiments described in this manuscript were performed with the approval of the IACUC at Johns Hopkins University School of Medicine.

1. Preparations

  1. Prepare the FACS Buffer, as described in Table 1.
  2. Ensure there is enough CO2 to euthanize the animals.
  3. Prepare the dissection space (place the bench pad and place the tape and dissection tools nearby).
  4. Label the 15 mL tubes, put 3 mL of HBSS with calcium a.......

Representative Results

Once the acquisition is complete and all the events are collected, the data should be analyzed according to standard flow cytometry practice. The focus of the analysis will vary depending on the individual goal of each experiment. In this case, quantification of intravascular and extravascular B-cells was pursued, and it was expressed as the number of cells per mg of tissue.

When using a spectral cytometer, it is recommended to start the analysis with an initial gating to remove debris with si.......

Discussion

A growing body of evidence indicates that B-cells play an important role in the context of myocardial physiology and myocardial remodeling/adaptation to injury7,8,9,10,11,12,13,36. Flow cytometry is an excellent tool to study immune cell populations in any .......

Acknowledgements

This study was funded by NHLBI grants 5K08HLO145108-03 and 1R01HL160716-01 awarded to Luigi Adamo.

The Aurora Flow Cytometer used to develop this study was funded by NIH Grant S10OD026859. We acknowledge the support of the JHU Ross Flow Cytometry Core.

....

Materials

NameCompanyCatalog NumberComments
Alexa Fluor 700 anti-mouse/human CD11b Antibody101222BioLegend100 µg 200 µL
(CellTreat 29481) Cell Strainer, 40 µm, BlueQBIAP303Southern Labware
0.5 mL Natural Microcentrifuge Tube1605-0000SealRite, USA Scientific
0.9% Sodium Chloride Injection, USP114-055-101Quality Biological0.90%
1.5 mL Natural Microcentrifuge Tube1615-5500SealRite, USA Scientific
10 µL Graduated TipOne Filter Tips11213810USA Scientific
1000 µL Graduated TipOne Filter Tips11267810USA Scientific
15 mL Centrifuge Tube, Plug Seal Cap, Polypropylene, RNase-/DNase-free430052Corning
1-Way Stop Valve, PolycarbonateSVPT951ECT Manufacturing
2,2,2-TribromoethanolT48402Sigma-Aldrich
200 µL Graduated TipOne Filter Tips11208810USA Scientific
3-Way Stop Valve, PolycarbonateSVPT953ECT Manufacturing
5 mL Polystyrene Round-Bottom Tube, 12 x 75 mm style352054Falcon, a Corning Brand
50 mL Centrifuge Tube, Plug Seal Cap, Polypropylene, RNase-/DNase-free430290Corning
ACK (Ammonium-Chloride-Potassium) Lysing Buffer118-156-101Quality BiologicalOsmolality: 290 + or -5% mOsm/Kg H20
Adapter 4x50ml, for 250 mL rectangular bucket in Rotor A-4-635810759005Eppendorf
Adapter for 15 mL Centrifuge Tubes, 9 Tubes per Adapter, Conical Bottom for use with Rotor Model A-4-6222638289Eppendorf
Adapter for 15 round-bottom tubes 2.6 – 7 mL, for 250 mL rectangular bucket in Rotor A-4-6222638246Eppendorf
Aluminum Foil 12 in x 75' Roll .0007UPC 109153Reynolds Wrap
Anesthesia Induction Chamber - MouseRWD-AICMV-100Conduct Science
BD Luer Slip Tip Syringe with attached needle 25 G x 5/8 in., sterile, single use, 1 mL309626BD Becton, Dickinson and Company
Brandzig Ultra-Fine Insulin Syringes 29G 1cc 1/2" 100-PackCMD 2613Brandzig
Brilliant Violet 421 anti-mouse CD19 Antibody115537BioLegend50 µg/mL
CAPS for Flow Tubes w/strainer mesh 35 µm, Dual position for 12 x 75 mm tubes, sterileT9009Southern Labware
Carbon Dioxide USP E CGA 940 CD USPEAirGas USA
Cole-Parmer Essentials Low-Form Beaker, Glass, 500 mLUX-34502-46Cole-Parmer
Collagenase 2LS004176Sigma-Aldrich
Connector brass chrome plated 1/4" female NPT x 1/4" barbY992611-AGAirGas USA
Cytek Aurora Flow CytometerCytek Biosciences
Diss 1080 Nipple 1/4 BARB CPM-08-12AirGas USA
DNase I - 40,000 UD4527Sigma-Aldrich
Easypet 3 - Electronic Pipette Controller4430000018Eppendorf
Electronic Balance, AX223/E30100606Ohaus Corp.
Eppendorf 5810R centrifuge5810REppendorf
Eppendorf Research plus 1-channel variable pipettesEppendorf
FlowJo 10.8.1BD Becton, Dickinson and Company
GLACIERbrand, triple density Ice Pan (IPAN-3100)Z740287Heathrow Scientific
HBSS (1x) - Ca2+ [+] Mg2+ [+]14025076gibco1x
HyaluronidaseH3506Sigma-Aldrich
Kelly Hemostats, Straight13018-14Fine Science Tools
Luer Slip Syringe sterile, single use, 20 mL302831BD Becton, Dickinson and Company
M1 Adj. Reg 0-100 PSI/CGA940M1-940-PGAirGas USA
McKesson Underpads, Moderate4033-CS150McKesson
Navigator Multi-Purpose Portable BalanceNV2201Ohaus Corp.
PBS pH 7.4 (1X) Ca2+ [-] Mg2+ [-]10010023gibco1x
PE anti-mouse/human CD45R/B220 Antibody103208BioLegend200 µg/mL
PerCP/Cyanine5.5 anti-mouse CD45 Antibody103132BioLegend100 µg 500 uL
Petri dish, Stackable 35 mm x 10 mm Sterile PolystyreneFB0875711YZFisher Scientific
Pkgd: Diss 1080 Nut/CO2/CO2-02M08-1AirGas USA
Powerful 6 Watt LED Dual Goose-Neck IlluminatorLED-6WAmScope
PrecisionGlide Needle 25 G x 5/8 (0.5 mm x 16 mm)305122BD Becton, Dickinson and Company
Purified Rat Anti-Mouse CD16/CD32 (Mouse BD Fc Block) Clone 2.4G2 (RUO)553141BD Becton, Dickinson and Company Biosciences0.5 mg/mL
R 4.1.1The R Foundation
Razor Blades9501250000Accutec Blades Inc
Regulator analytical two stage 0-25 psi delivery CGA320 3500 psi inletY12244A320-AGAirGas USA
Rotor A-4-62, incl. 4 x 250 mL rectangular bucketsRotor A-4-62Eppendorf
Serological pipette, plugged, 10 mL, sterile, non-pyrogenic/endotoxin-free, non-cytotoxic, 1 piece(s)/blister86.1254.001Sarstedt AG & Co KG
Sigma label tapeL8394Sigma-Aldrich
SpectroFlo 3.0.0Cytek Biosciences
Spex VapLock Luer Fitting, PP, Straight, Male Luer Lock x 1/8" Hose Barb; 1/EAMTLL230-6005Spex
Std Wall Lab Tubing, Size S2, Excelon, 1/8" ID x 3/16" OD x 1/32" Wall x 50' LongCG-730-003Excelon Laboratory
Syringe PP/PE without needle, 3 mLZ683566Millipore Sigma
Syringe pump55-1199 (95-240)Harvard Apparatus
Thomas 3-Channel Alarm Timer TM105009371W13Thomas Scientific
Tube Rack, 12 positions, 6 for 5.0 mL and 15 mL tubes and 6 for 25 mL and 50 mL tubes, polypropylene, numbered positions, autoclavable30119835Eppendorf
Tube Rack, 12 positions, for 5.0 mL and 15 mL tubes, polypropylene, numbered positions, autoclavable30119827Eppendorf
TYGON R-3603 Laboratory Tubing, I.D. × O.D. 1/4 in. × 3/8 in.T8913 (Millipore Sigma)Tygon, Saint-Gobain
Vortex-Genie 2SI-0236Scientific Industries, Inc.
VWR Dissecting Forceps with Guide Pin with Curved Tips89259-946Avantor, by VWR
VWR Dissecting Scissors, Sharp Tip, 4½"82027-578Avantor, by VWR
VWR Incubating Orbital Shaker, Model 3500I12620-946Avantor, by VWR
Zombie Aqua Fixable Viability Kit423102BioLegend

References

  1. Adamo, L., Rocha-Resende, C., Mann, D. L. The emerging role of B lymphocytes in cardiovascular disease. Annual Review of Immunology. 38, 99-121 (2020).
  2. Gowans, J. L., Knight, E. J. The route of re-circulation of lymphocytes in the rat.

Explore More Articles

Flow CytometryMyocardial B cellsPerfusionDigestionIsolationAntibody PanelImmune Cell TypesHeartLungLiverB220 AntibodyEuthanasiaHBSSMinced HeartEnzymesDNase ICollagenase IIHyaluronidase

This article has been published

Video Coming Soon

JoVE Logo

Privacy

Terms of Use

Policies

Research

Education

ABOUT JoVE

Copyright © 2024 MyJoVE Corporation. All rights reserved