Detection of HTK protein in cell lines by Western blotting. (A) Proteins were immunoprecipitated from lysates of UT-7, BaF3/HTK, and BaF3/vector cells with anti-HTK MoAb, 38-1E. The immunoprecipitates were separated by SDS-PAGE (10% polyacrylamide) under reducing conditions, transferred, and probed with anti-HTK PoAb (upper column). The membrane was reprobed with anti-HTK PoAb that had been incubated with a 50-fold excess molar of HTKex-Fc (lower column). (B) Proteins in the cell lysates of surface-biotinylated cell lines were immunoprecipitated with 38-1E. Immune complexes were separated by SDS-PAGE (10% polyacrylamide) under reducing conditions, transferred, and probed with HRP-conjugated streptavidin. The positions of the molecular mass markers (in kilodaltons) are indicated on the left.