Localization of FGFRs in human sperm. Sperm cells were stained with anti FGFR1, FGFR2, FGFR3 and FGFR4 or rabbit <t>IgG</t> and a secondary antibody labeled with <t>Cy3.</t> The corresponding fields stained with FITC-PSA to assess acrosomal status are shown. Bar: 10 μm. On the right, a representative image of individual sperm is depicted; ( A ) sperm stained with anti FGFR antibody and Cy3-conjugated secondary antibody, ( B ) FITC-PSA, ( C ) merge.