Figure 4

Biotinylation of the soluble high affinity receptor FcεRI α-chain. A) Western blot gel retardation assay of culture supernatants from cells expressing αD1D2. Where indicated, cell cultures were supplemented with biotin for 24 h and dialyzed samples reacted with streptavidin. (B) ELISA on IgE-coated plates of αD1D2, revealed with anti-SV5 tag mAb or HRP-conjugated streptavidin. (C) Flow cytometry and immunofluorescence microscopy assay with biotinylated (red) or non-biotinylated (violet) αD1D2 on transfected A20 cells expressing human membrane IgE; the green signal corresponds to FITC-conjugated anti-human IgE (ε-chain specific) antibody.