Invitrogen™ CD55 Monoclonal Antibody (M033)

CD55 (decay-accelerating factor, DAF) is a GPI-anchored membrane glycoprotein that protects autologous cells from classical and alternative pathway of complement cascade. Bidirectional interactions between CD55 and CD97 are involved in T cell regulation and CD55 can regulate complement when bound to CD97. In tumors, CD55 promotes neoangiogenesis, tumorigenesis, invasiveness and evasion of apoptosis. CD55 is a 70 kDa glycoprotein (in erythrocytes) anchored in the membrane by glycosylphosphatidylinositol tail. In other cells, the apparent molecular weight is somewhat larger for CD55 and has a substantial content of O-glycans. CD55 binds to activated C4b or C3b complement fragments on the cell surface, preventing the assembly and accelerating the decay of both classical and alternative pathways. CD55 carries the Cromer related blood group antigens. Two alternatively spliced transcripts encoding CD55 have been identified, and the predominant transcript encodes a membrane-bound protein expressed on cells exposed to plasma component proteins but an alternatively spliced transcript produces a soluble protein present at much lower levels. CD55 has been studied to have a role in prostate cancer growth and survival.