Figure 2.

Vav^+/− T cells do not induce a concentrated MHC II accumulation phenotype on interaction with peptide-pulsed APCs. I-E^k-GFP-transfected A20 B cell lymphoma cells were loaded with 10 μM MCC agonist peptide and were used to stimulate either wild-type (WT) or vav^+/− T cells. The frequency of occurrence of different geometrical patterns of the I-E^k accumulation at the interface of T cell/APC couples is given. A “concentrated” accumulation pattern is defined in Fig. 1. A “defective” accumulation is either an accumulation that is not sustained during the course of the experiment or that is diffuse as defined in Fig. 1. Wild-type and vav^+/− mice nos. 1, 2, and 3 derived from different breedings were analyzed in independent experiments. The number of T cell/APC couples analyzed in each experiment for T cells from wild-type mice nos. 1, 2, and 3 was n = 11, n = 14, n = 13, and for T cell from vav^+/− mice nos. 1, 2, 3, it was n = 5, n = 19, and n = 7, respectively.