Sperm acrosome associated 3 protein expression in equine primordial, primary, secondary, and tertiary follicles

Granulosa cellThe objective of this study was to characterize the protein expression of sperm acrosome associated 3 (SPACA3) in the equine ovary. Formalin-fixed and paraffin-embedded ovarian sections from 16 horses were processed for routine immunohistochemistry for SPACA3. Representative images were digitally captured at 400 x magnification. In all mares, SPACA3 was expressed in granulosa cells of all stages of follicles. Expression of SPACA3 in all equine follicular stages suggests that this may be a permanent immunosterilant target for the management of feral horse herds. Additional research is needed to determine if horses can produce a robust humoral response to a SPACA3 vaccine to induce sustained infertility.