CD55

This antibody reacts with the CD55-antigen (also known as DAF protein), a 41,4 kD glycosylphosphatidylinositol (GPI)-anchored single chain glycoprotein also known as decay-accelerating factor. It is expressed on hematopoietic cells including erythrocytes and many non-hematopoietic cells. This protein recognizes C4b and C3b fragments that condense with cell-surface hydroxyl or amino groups when nascent C4b and C3b are locally generated during C4 and c3 activation. Interaction of DAF with cell-associated C4b and C3b polypeptides interferes with their ability to catalyze the conversion of C2 and factor B to enzymatically active C2a and Bb and thereby prevents the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade . CD55 has been reported to reduce the efficiency of NK cell lysis and induce signal transduction in T cells. CD55 has also been shown to interact with CD97 and bind to Coxsackie and Echovirus.