Non-specific binding of monoclonal human erythropoietin antibody AE7A5 to Escherichia coli and Saccharomyces cerevisiae proteins.

摘要

The only monoclonal antibody currently recommended by the World Anti-Doping Agency (WADA) for the detection of erythropoietin (EPO) for anti-doping detection purposes in human urine is the mouse derived IgG_(2a) clone number AE7A5 (R&D Systems). This antibody AE7A5 acts as the critical reagent set by the WADA, for the evaluation of drug abuse by athletes. We have previously reported the cross-reactivity of the AE7A5 antibody with other human urinary proteins apart from EPO . AE7A5 anti-EPO antibody shows reactivity against at least four other human urinary proteins in the pH range 3-5 such as Tamm Horsfall glycoprotein, alpha-antichymotrypsin, alpha2 thiol proteinase inhibitor and alpha2 HS glycoprotein. This cross reactivity most likely occurs because of sequence homology between the reactive EPO epitope and epitopes contained within the cross-reacting proteins. Both endogenously produced (i.e., natural) and recombinant EPO separate in the pH range between pI 2 and 6 which is the basis of the currently used one-dimensional (1-D) iso-electric focusing (IEF) test for EPO detection , This non-specific binding nature of the EPO antibody AE7A5 to other relatively abundant urinary proteins which separate in the same pH range as both endogenous and recombinant EPO (epoetin alfa) raises the likelihood for false-positive detection of recombinant EPO in the currently used WADA approved anti-doping test .