“…We immunized 10-week-old nontransgenic BCF-1 mice and transgenic mice of lines 304, 192, and 242 with Ret protein, and examined the antigen (Ret)-dependent T-cell proliferation response in Figure 2 Time course of Ret protein expression in skin, thymus and brain from MT/ret transgenic mice of lines 304, 192, and 242. In (a) (line 304), (b) (line 192) and (c) (line 242), levels of Ret protein expression in indicated tissues (Sk, skin; Th, thymus; Br, brain) from the transgenic mice of dierent ages (F, fetus; N, newborn) were determined by Western blotting with anti-Ret antibody (Takahashi et al, 1993) according to the method described previously (Kato et al, 1994). In (d) autophosphorylation levels of Ret tyrosine kinase in the skin from the MT/ret transgenic mice of line 304 (0.0 ± 0.5 day-old), 192 (1.0 ± 1.5 dayold), and 242 (7.0 ± 7.5 day-old) were examined by immunoprecipitation with anti-Ret antibody followed by Western blotting with anti-phosphotyrosine antibody (D1; Transduction Laboratories, Lexington, KY, USA) or anti-Ret antibody (D2) vitro using a previously established method (Corradin et al, 1977;Dai et al, 1994).…”