Fig. 3. Two-dimensional NEPHGE/NaDodSO₄/PAGE of reprecipitated PTK polypeptides.

The anti-PTK antiserum and the anti-CD4 antibody were used to precipitate antigen from Con A-stimulated peripheral blood lymphocytes. Immunoprecipitates were then subjected to labeling with [³²P]ATP, as described in Fig. 1. The labeled polypeptides were eluted from protein A-Sepharose beads by boiling in the presence of 1% (wt/vol) NaDodSO₄ for 5 min and diluting 1:10 in Nonidet P-40 lysis buffer. The anti-PTK antiserum was then used to precipitate antigen from these preparations followed by three washes in lysis buffer and two-dimensional NEPHGE as described (36, 39). (Upper) Anti-PTK precipitated from an anti-PTK immunoprecipitate; (Lower) anti-PTK precipitated from an anti-CD4 immunoprecipitate.