Monitoring B Cell Activation with Antigenic Liposomes using a Calcium-Flux Assay

Published: November 30, 2023

Abstract

Source: Bednar, K. J. et al., Antigenic Liposomes for Generation of Disease-specific Antibodies. J. Vis. Exp. (2018)

This video showcases the assessment of B cell activation through the utilization of antigenic liposomes. B cells treated with calcium-sensitive Indo-1 dye are distinguished using flow cytometry, and their violet-to-blue fluorescence ratio is analyzed. As the cells encounter antigenic liposomes, it triggers B cell activation through calcium influx, progressively enhancing the violet-to-blue fluorescence signal ratio over time.

Protocol

1. Conjugation of Protein Antigen to PEGylated Lipid Add 3 g of cross-linked dextran gel beads with a fractionation range of 1,500–30,000 Daltons (Da) to a 250 mL vacuum flask. Add 60 mL of phosphate-buffered saline (PBS) and continually stir with a magnetic stir bar. Seal the flask and attach it to a vacuum to initiate de-gassing on a stir plate for a minimum of 1 h. In a 1.0 cm x 30 cm glass chromatography column with the turnover stopper closed, add PBS to the column to was…

Representative Results

Figure 1: Representative gating strategy, calcium flux results, and analysis. (A) Cells were analyzed through the following gating strategy: live lymphocytes (FSC-A vs. SSC-A), single cells (FSC-W vs. SSC-W), and B-cells (B220+CD5-). (B) The Indo-1/Ca2+ flux response (violet <em…

Divulgazioni

The authors have nothing to disclose.

Materials

Model 2110 Fraction Collector BioRad 7318122
Cholestrol Sigma C8667 Sigma grade 99%
SPDP Thermo Fisher Scientific 21857
DSPC Avanti 850365
DSPE-PEG 18:0 Avanti 880120
DSPE-PEG Maleimide Avanti 880126
Extruder Avanti 610000 1mL syringe with holder/heating block
Filters 0.1 µm Avanti 610005
Filters 0.8 µm Avanti 610009
10mm Filter Supports Avanti 6100014
Glass Round Bottom Flask Sigma Z100633
Turnover stoppers Thermo Fisher Scientific P-301398
Tubing Thermo Fisher Scientific P-198194
Leur Lock Thermo Fisher Scientific k4201634503
Sephadex G50 Beads GE Life Sciences 17004201
Sephadex G100 Beads GE Life Sciences 17006001
Heat Inactivated Fetal Calf Serum Thermo Fisher Scientific 10082147
HEPES (1M) Thermo Fisher Scientific 15630080
EGTA Sigma E3889
Penicillin-Streptomycin (10,000 U/mL) Thermo Fisher Scientific 15140122
1x RBC lysis Buffer Thermo Fisher Scientific 00-4333-57
Indo-1 Invitrogen I1203
CD5-PE BioLegend 100608
B220-PE-Cy7 BioLegend 103222
HBSS Thermo Fisher Scientific 14170112 Without calcium and magnesium
MgCl2 Sigma M8266
CaCl2 Sigma C4901
Fab anti-mouse IgM Jackson ImmunoResearch 115-007-020
F(ab')2 anti-mouse IgM Jackson ImmunoResearch 115-006-020

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Citazione di questo articolo
Monitoring B Cell Activation with Antigenic Liposomes using a Calcium-Flux Assay. J. Vis. Exp. (Pending Publication), e21873, doi: (2023).

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