Antibodies that specifically bind to novel serine protease polypeptides are disclosed. The polypeptides are selected from the group consisting of a polypeptide as shown in SEQ ID NO:2 from residue 1 through residue 373, a polypeptide as shown in SEQ ID NO:15 from residue 1 through residue 373, and a polypeptide as shown in SEQ ID NO:18 from residue 1 through residue 364.