Fig. 5. Localization of CSK in spermatozoa. (A-C) Murine spermatozoa from the cauda epididymis were fixed, washed and subjected to immunocytochemistry with anti-CSK antibody as described in Materials and Methods. The no-primary antibody controls (A,B) and the anti-CSK images (C,D) were visualized by fluorescence (lower panels) or phase-contrast (upper panels) microscopy.