Distinct forms of DAF in urine and blood.
DAF is a GPI-anchored protein expressed on all blood cells and most other cell types. This complement regulatory protein functions intrinsically in cell membranes to protect host cells from autologous complement attack. A soluble form is found in body fluids. In human urine, two forms of DAF have been described. Here we report that these two forms correspond to soluble DAF and to DAF bound onto urinary vesicles. With a newly established, highly sensitive ELISA, the proportion of these two forms could be quantified in healthy individuals and patients having renal disorders. This ELISA allowed us to measure DAF on blood cells and also in plasma. In contrast to urine, human plasma contained only soluble DAF when the plasma was thoroughly depleted of platelets. The concentration of soluble DAF in human serum was always lower than in the corresponding plasma, suggesting that this form might adhere to the clot during the coagulation process.
Miot
Sylvie
S
Department of Research, Immunonephrologie, Kantonsspital Basel, Hebelstrasse 20, 4031, Basel, Switzerland. Sylvie.Miot@unibas.ch
Crespo
Sophie
S
Schifferli
Jürg Alfred
JA
D018958:CD55 Antigens / Q000097:blood* / Q000652:urine*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity
D018958:CD55 Antigens