Fig. 3.
Phosphotyrosine blot of the nuclear fraction of Jurkat 76.25 cells after MHC-I ligation. Cells (3 × 107) were preincubated with PBS (lane 1) or saturating amounts of anti-β2M Ab (lanes 2 and 3) before exposure to avidin for the indicated time. The separated proteins were immunoblotted with antiphosphotyrosine Ab.