This family consists of several variants of the human and chimpanzee sperm antigen proteins (HE2 and EP2 respectively). The EP2 gene codes for a family of androgen-dependent, epididymis-specific secretory proteins.The EP2 gene uses alternative promoters and differential splicing to produce a family of variant messages. The translated putative protein variants differ significantly from each other. Some of these putative proteins have similarity to beta-defensins, a family of antimicrobial peptides [1].

1: Multiple promoter and splicing mRNA variants of the epididymis-specific gene EP2. Frohlich O, Po C, Murphy T, Young LG; J Androl 2000;21:421-430. PMID:10819450