Fig. 3.

Humanized antibodies block FSH binding to the FSH receptor. Representative flow cytometry histograms showing binding of Alexa647-FSH (*FSH; red) to HEK293 cells that were stably transfected to express human FSHR [confirmed by FSHR antibody (Ab; Invitrogen, PA-50963), shown in purple]. Of note is that the FSH blocking antibodies Hu6, Hu26, and H28; the mouse–human chimera CH1; and the epitope-targeted polyclonal antibody inhibited *FSH binding (light green). Gray histograms indicate no added *FSH. Expectedly, there are no shifts with FSHR Ab, secondary (2°) Ab, or *FSH in untransfected HEK293 cells. Inhibition of *FSH binding shown as median fluorescence intensity (MFI); mean ± SEM from three experiments; unpaired t test, **P < 0.01. RFU, relative fluorescence unit.