Immunogen sequence: ITRFLTEFQD KQIKDWKKRF IGIRMRTITP SLVDELKASN PDFPEVSSGI YVQEVAPNSP SQRGGIQDGD IIVKVNGRPL VDSSELQEAV LTESPLLLEV RRGNDDLLFS IAP. HtrA3 belongs to the human high-temperature requirement factor A (HtrA) family. It is also called pregnancy-