F-actin capping is impaired in T-CVID T cells. (A) Relative percentage of F-actin cap formation in PBLs from the 4 patients with T-CVID and a disease control patient (expressed as percentage capping in PBL from healthy controls; n = 6), as measured by confocal microscopy of cells labeled with fluorochrome-conjugated phalloidin. Error bars represent SD. Representative examples of F-actin labeling in cells not stimulated (no act) or activated for 1 hour by CD3/CD28 costimulation are shown at the top. (B-C) Immunoblot analysis of p38 (B) and JNK (C) phosphorylation using phosphospecific antibodies of postnuclear supernatants of PBL from patients with T-CVID and 1 or 2 representative healthy controls (ctr). 0 indicates nonstimulated; CD3, activated by CD3 cross-linking with OKT3 mAb for 5 minutes; and WB, Western blot. Filters were probed with anti-phospho-p38 or anti-phospho-JNK antibodies and, after stripping, with anti-p38 antibodies as loading control.