Figure 3
Figure 3. Intrinsic LFA-1 adhesiveness is dramatically reduced in Kindlin-3–deficient T cells, whereas VLA-4 adhesiveness is retained. (A) Spontaneous LFA-1 adhesiveness of control and LAD-III–derived effector T cells to medium and high densities of ICAM-1. Frequencies of transient and firm attachments (tethers) measured at a shear stress of 0.5 dyn/cm2 in 2 fields are depicted for the indicated groups. C indicates control; L, LAD-III. (Top inset) Effect of blocking ICAM-1–induced I-domain activation of LFA-1 with the allosteric inhibitor, XVA143, on the arrest fraction of control effector lymphocytes attaching to the high density ICAM-1. (Right panel) The fraction of total β2 integrin (stained by the TS1.18 mAb) that expresses the 327C epitope was compared between control and LAD-III–derived effector T cells. (B) Spontaneous LFA-1–dependent adhesion strengthening developed by effector cells settled for 1 minute on ICAM-1 and subjected to detachment by increasing shear forces was determined, as in panel D. *P < .05 for the percentage of initially settled control versus LAD-III cells that remained adhered at 2 dyn/cm2. (C) Spontaneous tethering (transient, rolling, or firm arrest) of cells interacting with medium and high density VCAM-1 determined at a shear stress of 0.75 dyn/cm2. The frequency and strength of all tethers were determined in 2 fields. Results are given as the mean ± range. *P < .05 for firm tethers of LAD-III versus control cells. (Right panel) The fraction of total β1 integrin (stained by the β1 mAb TS2.16) that expresses the activation neoepitope HUTS21 was compared between control and LAD-III–derived effector T cells. (D) VLA-4–dependent adhesion strengthening of control and LAD-III effector T cells. Lymphocytes were settled on VCAM-1 for 1 minute and then subjected to incremented shear forces. The percentage of initially settled T cells that resisted detachment from the substrate at the indicated shear forces was determined, as in panel B. N.S. indicates a nonsignificant P value. Data shown in panels A through D are each representative of 3 experiments, and all LAD-III effector lymphocytes were from patient B.

Intrinsic LFA-1 adhesiveness is dramatically reduced in Kindlin-3–deficient T cells, whereas VLA-4 adhesiveness is retained. (A) Spontaneous LFA-1 adhesiveness of control and LAD-III–derived effector T cells to medium and high densities of ICAM-1. Frequencies of transient and firm attachments (tethers) measured at a shear stress of 0.5 dyn/cm2 in 2 fields are depicted for the indicated groups. C indicates control; L, LAD-III. (Top inset) Effect of blocking ICAM-1–induced I-domain activation of LFA-1 with the allosteric inhibitor, XVA143, on the arrest fraction of control effector lymphocytes attaching to the high density ICAM-1. (Right panel) The fraction of total β2 integrin (stained by the TS1.18 mAb) that expresses the 327C epitope was compared between control and LAD-III–derived effector T cells. (B) Spontaneous LFA-1–dependent adhesion strengthening developed by effector cells settled for 1 minute on ICAM-1 and subjected to detachment by increasing shear forces was determined, as in panel D. *P < .05 for the percentage of initially settled control versus LAD-III cells that remained adhered at 2 dyn/cm2. (C) Spontaneous tethering (transient, rolling, or firm arrest) of cells interacting with medium and high density VCAM-1 determined at a shear stress of 0.75 dyn/cm2. The frequency and strength of all tethers were determined in 2 fields. Results are given as the mean ± range. *P < .05 for firm tethers of LAD-III versus control cells. (Right panel) The fraction of total β1 integrin (stained by the β1 mAb TS2.16) that expresses the activation neoepitope HUTS21 was compared between control and LAD-III–derived effector T cells. (D) VLA-4–dependent adhesion strengthening of control and LAD-III effector T cells. Lymphocytes were settled on VCAM-1 for 1 minute and then subjected to incremented shear forces. The percentage of initially settled T cells that resisted detachment from the substrate at the indicated shear forces was determined, as in panel B. N.S. indicates a nonsignificant P value. Data shown in panels A through D are each representative of 3 experiments, and all LAD-III effector lymphocytes were from patient B.

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