Journal: Cancer Immunology Research
Article Title: Granulocyte–Macrophage Colony-Stimulating Factor Influence on Soluble and Membrane-Bound ICOS in Combination with Immune Checkpoint Blockade
doi: 10.1158/2326-6066.CIR-22-0702
Figure Lengend Snippet: Suppressive effects of sICOS-SV on the costimulation of T cells. A, CHO-K1 cells were transduced with either ICOSL-expressing lentiviral vector or GFP-empty vector (CHO-ICOSL − ) as a negative control. Expression of ICOSL on the cell surface of CHO-K1 was examined by flow cytometry using anti-ICOSL (open histogram with solid line) or lentivirus GFP-empty vector (open histogram with dotted line). Isotype antibody was used as a negative control (filled histogram). B, ICOSL-expressing CHO-K1 cells were stained with ICOS-SV Ig (red line), control IgG Ig (blue line), or PD-1 Ig (orange line) and analyzed by flow cytometry. Both soluble control Ig and PD-1 Ig were used as negative controls. GFP-empty vector-expression CHO-K1 cells stained with ICOS-SV Ig (green line) were used as another negative control for the binding assay. Isotype antibody control was used as a negative control (gray filled histogram). C, CD154 expression was determined by FACS analysis. Isotype control antibody is shown in gray. Activated T cells treated with a suboptimal dose of anti-CD3 were incubated with control Ig + CHO-ICOSL − cells (CHO cells transduced with GFP-empty vector, blue), control Ig + CHO-ICOSL + cells (green), PD-1 Ig + CHO-ICOSL + cells (red), or ICOS-SV Ig + CHO-ICOSL + cells (yellow). Both control Ig and PD-1 Ig were used as negative controls. D, Two-tailed unpaired t test was used to compare expression of CD154 between two groups. **, P < 0.01; ***, P < 0.001. Standard deviation of the mean (SD) is shown. E, CD69 expression was determined by FACS analysis. Isotype control antibody is shown in gray. Activated T cells treated with a suboptimal dose of anti-CD3 were incubated with control Ig + CHO-ICOSL − cells (CHO cells transduced with GFP-empty vector, blue), control Ig + CHO-ICOSL + cells (green), PD-1 Ig + CHO-ICOSL + cells (red), or ICOS-SV Ig + CHO-ICOSL + cells (yellow). Both control Ig and PD-1 Ig were used as negative controls. F, Two-tailed unpaired t test was used to compare expression of CD69 between the two groups. **, P < 0.01; ***, P < 0.001. Standard deviation of the mean (SD) is shown. G, CHO cells transduced with GFP-empty vector (CHO-ICOSL − ) were used as negative controls. Sample loading was normalized to total pan-Akt. H, T-cell proliferation was determined by a [ 3 H]-TdR thymidine incorporation assay. CHO cells transduced with empty vector (CHO-ICOSL − ) were used as negative controls. Two-tailed unpaired t test was used to compare 3 H uptake between the two groups, respectively. *, P < 0.1. Standard deviation of the mean (SD) is shown. I, Schematic diagram of ICOS/ICOSL costimulatory T-cell proliferation, as well as the blocking function of the sICOS-SV. Depicted are the cytoplasmic tail sequences of ICOS-FL and sICOS-SV isoforms. The YMFM Src Homology 2 (SH2) binding motif in the cytoplasmic tail of the ICOS-FL is highlighted in pink. Upon ICOS engagement by the ICOSL on CHO cells, the unique YMFM motif recruits a p85a and a p50a subunits of PI3K, resulting in the elevated phosphorylation of Akt, thereby inducing PI3K activity. In contrast, the ICOS-SV, a truncated isoform lacking the YMFM motif in its cytoplasmic tail, cannot elicit phosphorylation of Akt. Consequently, it fails to promote T-cell proliferation. The secreted ICOS-SV (red) competes with membrane-bound ICOS for binding to ICOSL, thereby blocking the interaction between ICOSL and membrane ICOS. As a result, the sICOS-SV suppresses phosphorylation of Akt and T-cell proliferation, leading to the inhibition of T-cell immunity. The diagram was created with BioRender.com. All data shown are representative of at least 2 independent experiments.
Article Snippet: Monoclonal antibodies specific for CD3 (UCHT1), CD4 (RPA-T4), CD8 (HIT8a), CD28 (CD28.2), CD25 (BC96), ICOSL (2D3), CD14 (63D3), HLA-DR (L243), CD11C (3.9), CD80 (2D10), CD86 (BU63), CD83 (HB15e), human IgG1 Fc (QA19A42), GITR (108- ), CD154 , CD69 (FN50), ICOS (C398.4A), mouse IgG1 k istotype control (MOPC-21), mouse IgG2b k isotype control (MPC-11), mouse IgG2a k isotpe control (MOPC-173), and Armenian Hamster IgG isotype control (HTK888) were purchased from BioLegend.
Techniques: Transduction, Expressing, Plasmid Preparation, Negative Control, Flow Cytometry, Staining, Control, Binding Assay, Incubation, Two Tailed Test, Standard Deviation, Thymidine Incorporation Assay, Blocking Assay, Phospho-proteomics, Activity Assay, Membrane, Inhibition
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![Suppressive effects of sICOS-SV on the costimulation of T cells. A, CHO-K1 cells were transduced with either ICOSL-expressing lentiviral vector or GFP-empty vector (CHO-ICOSL − ) as a negative control. Expression of ICOSL on the cell surface of CHO-K1 was examined by flow cytometry using anti-ICOSL (open histogram with solid line) or lentivirus GFP-empty vector (open histogram with dotted line). Isotype antibody was used as a negative control (filled histogram). B, ICOSL-expressing CHO-K1 cells were stained with ICOS-SV Ig (red line), control <t>IgG</t> Ig (blue line), or PD-1 Ig (orange line) and analyzed by flow cytometry. Both soluble control Ig and PD-1 Ig were used as negative controls. GFP-empty vector-expression CHO-K1 cells stained with ICOS-SV Ig (green line) were used as another negative control for the binding assay. Isotype antibody control was used as a negative control (gray filled histogram). C, CD154 expression was determined by FACS analysis. Isotype control antibody is shown in gray. Activated T cells treated with a suboptimal dose of anti-CD3 were incubated with control Ig + CHO-ICOSL − cells (CHO cells transduced with GFP-empty vector, blue), control Ig + CHO-ICOSL + cells (green), PD-1 Ig + CHO-ICOSL + cells (red), or ICOS-SV Ig + CHO-ICOSL + cells (yellow). Both control Ig and PD-1 Ig were used as negative controls. D, Two-tailed unpaired t test was used to compare expression of CD154 between two groups. **, P < 0.01; ***, P < 0.001. Standard deviation of the mean (SD) is shown. E, CD69 expression was determined by FACS analysis. Isotype control antibody is shown in gray. Activated T cells treated with a suboptimal dose of anti-CD3 were incubated with control Ig + CHO-ICOSL − cells (CHO cells transduced with GFP-empty vector, blue), control Ig + CHO-ICOSL + cells (green), PD-1 Ig + CHO-ICOSL + cells (red), or ICOS-SV Ig + CHO-ICOSL + cells (yellow). Both control Ig and PD-1 Ig were used as negative controls. F, Two-tailed unpaired t test was used to compare expression of CD69 between the two groups. **, P < 0.01; ***, P < 0.001. Standard deviation of the mean (SD) is shown. G, CHO cells transduced with GFP-empty vector (CHO-ICOSL − ) were used as negative controls. Sample loading was normalized to total pan-Akt. H, T-cell proliferation was determined by a [ 3 H]-TdR thymidine incorporation assay. CHO cells transduced with empty vector (CHO-ICOSL − ) were used as negative controls. Two-tailed unpaired t test was used to compare 3 H uptake between the two groups, respectively. *, P < 0.1. Standard deviation of the mean (SD) is shown. I, Schematic diagram of ICOS/ICOSL costimulatory T-cell proliferation, as well as the blocking function of the sICOS-SV. Depicted are the cytoplasmic tail sequences of ICOS-FL and sICOS-SV isoforms. The YMFM Src Homology 2 (SH2) binding motif in the cytoplasmic tail of the ICOS-FL is highlighted in pink. Upon ICOS engagement by the ICOSL on CHO cells, the unique YMFM motif recruits a p85a and a p50a subunits of PI3K, resulting in the elevated phosphorylation of Akt, thereby inducing PI3K activity. In contrast, the ICOS-SV, a truncated isoform lacking the YMFM motif in its cytoplasmic tail, cannot elicit phosphorylation of Akt. Consequently, it fails to promote T-cell proliferation. The secreted ICOS-SV (red) competes with membrane-bound ICOS for binding to ICOSL, thereby blocking the interaction between ICOSL and membrane ICOS. As a result, the sICOS-SV suppresses phosphorylation of Akt and T-cell proliferation, leading to the inhibition of T-cell immunity. The diagram was created with BioRender.com. All data shown are representative of at least 2 independent experiments.](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_8357/pmc10398357/pmc10398357__1100fig3.jpg)
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