Fig. 3.

Mixed lymphocyte reaction (MLR) with irradiated Raji cells and Jurkat cells. Proliferation was measured by bromodeoxyuridine incorporation on day 2 of culture. Results are shown as percentage-stimulation of spontaneous proliferation (control). CTLA4-Ig inhibited proliferation, whereas elutes containing CD28 autoantibodies significantly stimulated T cell proliferation. Co-stimulation with CTLA4-Ig and autoantibodies against CD28 resulted in a significantly reduced inhibition of Jurkat cell proliferation. **P < 0·01 significant compared with control.