A Flow Cytometry Assay to Identify Immune Cell Subsets in Peripheral Blood Mononuclear Cells
Transcription
To prepare the PBMCs for staining, transfer 100 microliters of each sample to a 96-well V-bottom plate. Centrifuge the plate at 350 times g for three minutes at room temperature. Carefully, aspirate the supernatant without disturbing the cell pellet. To each well, add 100 microliters of PBS containing a live/dead fixable dye that reacts with free amine on proteins, and resuspend the PBMC mixture carefully.
Subsequently, allow the plate to sit for 10 minutes at room temperature for labeling of dead cells. For each sample, prepare 30 microliters of a mix containing all seven antibodies. At this stage, titrated antibodies against different target molecules and in different fluorochromes can be added as well. Centrifuge the 96-well plate at 350 times g for three minutes at room temperature, and carefully aspirate the supernatant without disturbing the cell pellet.
Add the antibody cocktail to each well, and resuspend carefully without generating bubbles. Incubate for 30 minutes at room temperature in the dark. After 30 minutes, add 150 microliters of staining buffer to each well, and centrifuge the plate at 350 times g for three minutes at room temperature. Carefully aspirate the supernatant without disturbing the cell pellet, and resuspend the cells in 200 microliters of PBS. The cells are now ready for flow cytometry analysis.
To begin this two-fluorochrome, seven-marker gating strategy, select the lymphocyte gate and create a dot-plot with one of the two fluorochromes used in this protocol on each axis. Gate on CD8-positive T cells, identified as CD3 and CD8 double-positive cells at the top-right corner of the dot-plot. Exclude the dim CD8 population, which might contain NK T cells. Gate on CD4-positive T cells, identified as the population in between CD8-positive T cells and the CD3 single-positive populations.
Gate on gamma-delta T cells, identified as high CD3 cells. Subdivide gamma-delta T cells to CD8-positive and CD8-negative. Gate on NK cells, identified as the population in between CD3-positive and CD3-negative cells. Subdivide the NK cells to CD8-positive and CD8-negative Gate on B cells, identified as the CD3-negative, CD19-positive population on the lower right corner of the dot-plot.
Select the monocyte gate and create a dot-plot with one of the two fluorochromes used in this protocol on each axis. Gate on the CD3-negative, CD14-positive population.
