Cd19 bv510

Lymphocytes isolated from whole blood via Ficoll-Paque Plus gradient centrifugation (GE Healthcare) from 16 healthy volunteers were stained extracellularly with antibodies to determine expression of HLA-C on various subsets. The antibodies used were: CD3 [clone UCHT1] BV605, CD19 [clone HIB19] PE-Cy7, CD56 [clone HCD56] BV711 (BioLegend, San Diego, CA, USA); CD4 [clone SK3] PE-Cy7, CD8 [clone RPA-T8] APC (BD Biosciences, Franklin Lakes, NJ, USA); HLA-C [clone DT9] conjugated to AlexaFluor488. Data from the samples collected on a BD LSRFortessa flow cytometer were analyzed using FlowJo v10.1. Mononuclear cells from additional blood donors and from indicated tissues were analyzed by flow cytometry at the Karolinska Institutet, Stockholm, Sweden. The following additional antibodies were used: CD3 [clone UCHT1] PE-Cy5 (Beckman Coulter, Brea, CA, USA); CD19 BV510 (Biolegend); NKG2A [clone Z199] BB515, CD56 [clone NCAM16.2] BUV737, CD57 [clone NK-1] BV605, HLA-C [clone DT9] PE, KIR2DL2/3/S2 [clone CH-L] BUV395 (BD Biosciences); KIR2DL1/S1 [clone EB6] PC-5.5 (Beckman Coulter); KIR3DL1 [clone DX9] BV421 (Biolegend); KIR2DS4 [clone REA860] PE-Vio615 (Miltenyi Biotec, Cambridge, MA, USA). Live/Dead marker Aqua (Thermo Fisher Scientific) was also used. Samples were acquired on a 5 laser BD LSRFortessa flow cytometer and analyzed using FlowJo v10.1.

Donor PBMCs was stained with live-dead marker (1:1000; Invitrogen, LIVE/DEAD™ Fixable Near-IR Dead Cell Stain Kit) to gate out the dead cells for 20 min in 4 °C. After washing with FACS buffer, the cells were stained with respective B, T cell marker panel antibodies diluted in FACS buffer (1xPBS, 2% FBS, 0.1% sodium azide) at 4 °C for 30 min. B cell panel: CD19-BV510 (1:40; Biolegend, Cat. No. 363020), CD14-APC-Cy7 (1:50; BD, Cat. No. 557831), CD3-APC-Cy7 (1:125; Biolegend, Cat. No. 317342), CD10-PE-Dazzle594 (1:50; Biolegend, Cat. No. 312228), CD21-APC (1:50; Biolegend, Cat. No. 354906), CD27-BV650 (1:40; Biolegend, Cat. No. 302828), CD38-PE-Cy7 (1:40; Biolegend, Cat. No. 356608), PD-1-BV711 (1:20; Biolegend, Cat. No. 329928), IgD-BUV 737 (1:40; BD, Cat. No. 612798), IgG-PerCP (1:40; BD), IgA-PE (1:40; Miltenyi, Cat. No. 130-114-002). T cell panel: CD14-APC-Cy7 (1:50; BD, Cat. No. 557831), CD19-APC-Cy7 (1:50; BD, Cat. No. 557791), CD3-BUV395 (1:40; BD, Cat. No. 563546), CD4-BUV496 (1:40; BD, Cat. No. 612936), CD8-PE (1:40; BD, Cat. No. 555367), CXCR5-PE-Cy7 (1:100; BD, Cat. No. 624052), CD25-BV421 (1:40; BD, Cat. No. 562442), CD127-FITC (1:20; BD, Cat. No. 557938). The samples were then washed, resuspended in FACS buffer and analysed on BD LSRFortessa flow cytometer (Data availability—Figshare 10.6084/m9.figshare.23549964).

Tissues were harvested and processed as described previously (11 (link)). After incubation with anti-FcReceptor, cells were stained with CD44-FITC, CD8α-PerCP (eBioscience), CD69-APC-Cy7, CD19-BV510, and CD4-BV711 (BioLegend) for 20 min on ice. For intracellular staining of FoxP3-PE (eBioscience), cells were fixed and permeabilized with Mouse Foxp3 Buffer set (BD Biosciences) after surface staining, according to the manufacturer’s instructions. Samples were run on a BD LSRFortessa analyzer and the results evaluated in FlowJo. Data were plotted in GraphPad Prism for statistical analysis.

Donor PBMCs was stained with live-dead marker (1:1000; Invitrogen, LIVE/DEAD™ Fixable Near-IR Dead Cell Stain Kit) to gate out the dead cells for 20 min in 4 °C. After washing with FACS buffer, the cells were stained with respective B, T cell marker panel antibodies diluted in FACS buffer (1xPBS, 2% FBS, 0.1% sodium azide) at 4 °C for 30 min. B cell panel: CD19-BV510 (1:40; Biolegend, Cat. No. 363020), CD14-APC-Cy7 (1:50; BD, Cat. No. 557831), CD3-APC-Cy7 (1:125; Biolegend, Cat. No. 317342), CD10-PE-Dazzle594 (1:50; Biolegend, Cat. No. 312228), CD21-APC (1:50; Biolegend, Cat. No. 354906), CD27-BV650 (1:40; Biolegend, Cat. No. 302828), CD38-PE-Cy7 (1:40; Biolegend, Cat. No. 356608), PD-1-BV711 (1:20; Biolegend, Cat. No. 329928), IgD-BUV 737 (1:40; BD, Cat. No. 612798), IgG-PerCP (1:40; BD), IgA-PE (1:40; Miltenyi, Cat. No. 130-114-002). T cell panel: CD14-APC-Cy7 (1:50; BD, Cat. No. 557831), CD19-APC-Cy7 (1:50; BD, Cat. No. 557791), CD3-BUV395 (1:40; BD, Cat. No. 563546), CD4-BUV496 (1:40; BD, Cat. No. 612936), CD8-PE (1:40; BD, Cat. No. 555367), CXCR5-PE-Cy7 (1:100; BD, Cat. No. 624052), CD25-BV421 (1:40; BD, Cat. No. 562442), CD127-FITC (1:20; BD, Cat. No. 557938). The samples were then washed, resuspended in FACS buffer and analysed on BD LSRFortessa flow cytometer (Data availability—Figshare 10.6084/m9.figshare.23549964).

B cell stimulation with a minor cocktail of stimuli was performed to study the effect of IL-21, co-stimulation, and BCR activation on plasmablast formation. CD19⁺ B cells were isolated via CD43 negative selection with CD43 MicroBeads (Miltenyi Biotec, Bergisch Gladbach, Germany) (purities ≥85%). B cells were incubated with anti-IL-21R antibody ATR-107 (10 μg/ml, Pfizer) or isotype-matched control (10 μg/ml IgG1-Fc, R&D systems). Next, cells were stimulated with 5 μg/ml soluble anti-CD40 (Bioceros, Utrecht, The Netherlands), 10 μg/ml goat-anti-human IgM (Jackson Immunoresearch, West Grove, PA, USA) and human recombinant IL-21 (100 ng/ml, eBioscience). Subsequently, the presence of plasmablasts on day 0 and the differentiation of memory B cells into plasmablasts on day 8 were determined with flow cytometry. Plasmablasts were defined as CD19^posCD27^highCD38^high cells (16 (link)). The following MoAbs were used: CD19 BV510 (Biolegend), CD27 Pe-Cy7 (eBioscience), IgD APC-Cy7 (Biolegend), and CD38 BV421 (BD Biosciences). In addition, viability staining with 7-AAD PerCP was performed (BD Biosciences).

We isolated peripheral blood mononuclear cells (PBMC) from peripheral blood by Ficoll gradient and we stored them in liquid nitrogen for batched analysis. For multicolor flow cytometry analyses, we used the following monoclonal antibodies: from Becton Dickinson (BD, Franklin Lakes, NJ), CD3-FITC, CD3-PerCP-Cy5.5, CD4-APC-Cy7, CD8-BV510, CD45RO-FITC, CD45RA-APC, CD45RA-APC-Cy7, CD71-PE, IgD-PerCP-Cy5.5, CD25-APC-Cy7, CD138-BV421, CCR4-PE, CD27-PE, CD95-BV421, CD28-BV421, TIM3-BV421, CCR6-BV421, CCR7-AF700, CXCR3-PE, IL-2-PE, IL-17-BV786, and IFN-γ-PE-Cy7; from Biolegend (San Diego, CA), CD19-BV510, CD56-FITC, CD27-APC, CD127-FITC, CD57-PerCp-Cy5.5, PD-1-APC-Cy7, CXCR5-FITC, LAG3-APC, IL-10-PerCP-Cy5.5, and TNF-α-FITC. From eBioscience (San Diego, CA), CD4-PE-Cy7, CD21-PE, and CD24-APC-Cy7 were used. From Miltenyi Biotec (Auburn, CA), CD25-APC and anti-KLRG1-PE were used. From Beckman Coulter (Indianapolis, IN), CD38-PE-Cy7 was used.
We performed intracellular staining for IL-2, IL-4, IL-17, IFN-g, and TNF-a together with extracellular markers for CD4⁺, CD8⁺, and CD19⁺. Cells were fixed and permeabilized using Intracellular Fixation and Permeabilization Buffer Set (eBioscience) according to the manufacturer’s instructions.
Data were acquired (> 1 × 10⁶ events) on a 3-laser FACSLyric flow cytometer (BD Biosciences) and analyzed with FlowJo^® software.