Proteins having the amino acid sequences represented by SEQ ID NOS: 2, 4, 6, 8 and 10; proteins having amino acid sequences derived from these amino acid sequences by deletion, substitution or addition of one to several amino acids; and base sequences encoding the same. Transgenic non-human animals with altered expression level of a serine protease BSSP2; an antibody against BSSP2; and a method for detecting BSSP2 in a specimen by using the antibody.