[Advances in the study of epididymal protease inhibitor]

The epididymal protease inhibitor (Eppin) has recently been cloned in human and mice, which is specifically expressed in the epididymis and testis. Eppin is a cystine-rich secretory protein which contains signal peptide, WAP and BPTI motifs. Eppin is involved in sperm maturation and fertilization, and in the innate immune system of human epididymis. Immunocontraception with Eppin is effective and reliable, but its safety is to be further proved. This paper summarizes the effects of Eppin of fertilization and immunity, as well as its utilization in immunocontraception.