Binlb is a rat epididymis specific β-defensin which may have fertility related functions in addition to its antimicrobial activity.β-defensins are cysteine-rich cationic antimicrobial peptides that have their important implications in innate and adaptive immunity.Though considerable numbers of new β-defensins have been discovered,few corresponding antibodies have been reported.The small peptide with special structure and antimicrobial nature of β-defensins make them very difficult to express in prokaryotic system.Here we adopted a double-copy protein expression scheme based on which not only the mBinlb protein was successfully expressed but also the immunity of the antigen was enhanced.The validity of the antisera was verified by using Weste blotting and immunohistochemical analyses.It will be a useful tool for deeply investigating the roles of Binlb and also provide a simple but effective method in raising antisera against other members of the β-defensin gene family.