EGF receptor-like determinants on human spermatozoa and their possible cytoskeletal association

The study was focused on the localization of human sperm epidermal growth factor receptor and its resistance to Triton X-100 extraction, indicating possible cytoskeletal association. Human spermatozoa were subjected to immunofluorescence and pre-embedding immunoelectron microscopy using anti-EGF receptor monoclonal antibody as a probe. In detergent-untreated cells, the entire head was stained with intensity declining towards the acrosomal tip. Triton-extracted spermatozoa were stained predominantly in the equatorial segment region. Electron microscopy performed after extraction revealed that the label was also present in the equatorial segment and localized to electron-dense material overlying the acrosomal remnants. This Triton-resistant staining could imply cytoskeletal association of the EGF receptor in the equatorial segment, with possible importance in fertilization.