Characterization of a new LAD-III patient. (A) Expression levels of β2 integrin αLβ2 (LFA-1) and β1 integrin α4β1 are equivalent between LAD-III patient and control T lymphoblasts (control cells: gray fill; patient cells: dark line; representative mAb control: dashed line; n = 2). (B) Adhesion to LFA-1 ligand ICAM-1 and α4β1/α5β1 ligand fibronectin after inside-out signaling mediated by phorbol ester (PdBu), Ca²⁺ mobilizer thapsigargin (Thaps), or CD3 mAb cross-linking of the T-cell receptor/CD3 complex (CD3XL) and “outside-in” signaling via Mg²⁺/EGTA treatment (samples in triplicate; n = 2). (C) Attachment of T lymphoblasts to ICAM-1. The parent T cells spread as expected, whereas the patient T cells were lightly attached and failed to spread. Images are representative of 25 cells/experiment; n = 3. Scale bar represents 10 μm.