PKC pathways required for CD3+ T-cell adhesion. Adhesion responses of primary CD3+ (A) and Jurkat (B) T cells in the presence of GF109203X or pan-PKC LMWI.21 The PKC inhibitors significantly reduced binding of T cells to ICAM-1 compared with dimethylsulfoxide (DMSO) controls (DMSO, n = 3; LMWI at 500 nM, n = 3; split-plot ANOVA, P = .013). (C-F) (Left panels) Activation-dependent adhesion of LFA-1 to ICAM-1 in CD3+ T cells derived from wt and PKC isotype-deficient mice. (Right panels) Adhesion of LFA-1 to ICAM-1 in Jurkat T cells expressing CA PKC isotype mutants.22,63 After a 30-minute incubation with medium or stimuli (CD3, CD3/CD28, or PDBu plus ionomycin, as indicated), T cells were analyzed. (Insets) Immunoblots of KO, wt, or transfected T cell lysates, as indicated. Binding to ICAM-1 was reduced significantly in PKC-θ KO CD3+ T cells compared with wt controls (PKC-θ+/+, n = 6; PKC-θ−/−, n = 6; split-plot ANOVA, P = .035). Under CD3-stimulated conditions, the binding of Jurkat T cells transfected with the PKC-θ CA mutant to ICAM-1 was higher than that of the GFP-transfected control but was just above the 0.5% significance level (GFP, n = 5; CA-PKC-θ, n = 5; split-plot ANOVA, P = .052). Results shown are the mean plus or minus SE of at least 3 independent experiments.
