Immunogen sequence: YCPAPPQIDN GIIQGERDHY GYRQSVTYAC NKGFTMIGEH SIYCTVNNDE GEWSGPPPEC RGKSLTSKVP PTVQKPTTVN VPTTEVSPTS QKTTTKTTTP NAQATRSTPV SRTTKHFHET TPNKGSGTTS GTTRLLSGHT CFTLTGLLGT LVTMG. CD55 (decay-accelerating factor, DAF) is a GPI-anchored membra