Figure 1.

TCR-induced proliferation and activation of IL-2 gene transcription in Vav^−/− T cells. (a) Proliferation of Vav^+/+ or Vav^−/− CD4⁺ splenic T cells in response to a range of concentrations of plate-bound anti-CD3 antibody in the presence or absence of soluble anti-CD28 antibody (10 μg/ml). Proliferation was assessed by the incorporation of ³H-thymidine during the final 4 hr of a 48 hr assay. Graph shows the mean ³H-thymidine incorporation (±SEM) of triplicate samples. (b) Induction of IL-2 gene transcription assessed by the production of luciferase by Vav^+/+ or Vav^−/−CD4⁺ T cells purified from mice carrying a luciferase transgene under the control of the IL-2 promoter. Cells were incubated for 24 hr either with plate-bound anti-CD3 (10 μg/ml) and soluble anti-CD28 (10 μg/ml) or in the absence of any added stimulus (medium). (c) Proliferation of Vav^+/+ or Vav^−/− CD4⁺ T cells in response to plate-bound anti-CD3 antibody (5 μg/ml) and soluble anti-CD28 antibody (10 μg/ml) in the absence or presence of ionomycin (198 ng/ml). Proliferation was assessed as in Fig. 1a.