WAP four-disulfide core domain protein 2 - also known as Human Epididymis Protein 4 (HE4) - is a protein that in humans is encoded by the WFDC2 gene.This gene encodes a protein that is a member of the WFDC domain family. The WFDC domain, or WAP Signature motif, contains eight cysteines forming four disulfide bonds at the core of the protein, and functions as a protease inhibitor in many family members. This gene is expressed in pulmonary epithelial cells, and was also found to be expressed in some ovarian cancers. The encoded protein is a small secretory protein, which may be involved in sperm maturation.

This antibody binds to its immunogen, and did not show any cross reactivity with unrelated antigens in ELISA. Cross reactivity with mouse and rat HE4 has not been tested yet.

Store at 4°C if intended for use within one month, otherwise, store at -20°C to -80°C. The lyophilized antibody is stable for at least 18 months after the date of receipt when stored at -20°C to -114°C. After reconstitution, it can be aliquoted and storedtory proteins expressed in gastrointestinal mucosa. Their functions are not defined, but they may protect the mucosa from insults, stabilize the mucus layer, and affect healing of the epithelium.