DQ 65-79 does not inhibit phosphotyrosine activity upon IL-2 stimulation. (a) Western blot using anti-phosphotyrosine mAb. (b) Western blot using anti-Fyn or anti-Lck. (c) Kinase activity of immunoprecipitated Fyn and Lck. NS, no stimulation; D, DMSO; Q, DQ 65-79; 72, DQ 65-79(72D); R, rapamycin.