Apc conjugated cd45ro

Peripheral blood mononuclear cells (PBMCs) were isolated from fresh blood by density gradient centrifugation on Ficoll-Paque PLUS (Cytiva). The isolated PBMCs were then analyzed with an 8-color flow cytometer (FACSCanto™II, BD Biosciences, CA, USA) after labeling with the following anti-human fluorochrome-conjugated antibodies: FITC-conjugated CD38 (clone HIT2); APC or FITC-conjugated PD-1 (clone EH12.2H7); FITC-conjugated CD45RA (clone HI100); PE-conjugated CD24 (clone ML5); PE-conjugated ICOS (clone C398.4A); PE-conjugated CCR6 (clone G034E3); PerCP-conjugated CD3 (clone UCHT1); PE/cyanine7-conjugated CD27 (clone O323); PE/cyanine7-conjugated CD4 (clone OKT4); APC-conjugated CD19 (clone HIB19); APC-conjugated CD45RO (clone UCHL1); APC-conjugated CXCR3 (clone G025H7); and Brilliant Violet 421-conjugated CXCR5 (clone J252D4) (all antibodies were from BioLegend, CA, USA). Cell viability was assessed using a live/dead assay (Fixable Viability Dye eFluor 780; eBioscience). All data were collected and analyzed using FlowJo software. The gating strategies of the isotype-matched IgG control for specific cell populations are shown in the supplementary figure (Figure S1).

To measure CAR expression, cells were first suspended in 100 μL of cold buffer (PBS containing 0.5% BSA and 2 mM EDTA) supplemented with 2 μg of goat IgG (Jackson Immunoresearch, West Grove, PA, USA) and incubated on ice. CD19-FLAG CAR-T cells were stained with 2 μL of PE- or Alexa Fluor 488-conjugated anti-FLAG (Biolegend), whereas BCMA CAR-T cells were first stained with 0.4 μg of BCMA-huFc protein (Acro Biosystems, Newark, DE, USA) and then stained with 1 μL of PE- or Alexa Fluor 488-conjugated goat anti-human IgG (Jackson Immunoresearch). Cells were co-stained with either FITC-conjugated anti-CD4 and APC-conjugated anti-CD8; PE-conjugated anti-CD27 and APC-conjugated CD45RO; or APC-conjugated anti-PD-1 (all from Biolegend). Dead cells were identified with 7-aminoactinomycin D (7-AAD, BioLegend). The cells were rinsed with 3 mL of buffer, then suspended in buffer and acquired on a FACSCalibur (BD Biosciences, San Jose, CA, USA). Gating strategies are shown in Supplemental Figure S1.