Isolation and characterization of conformation sensitive antierythropoietin monoclonal antibodies: effect of disulfide bonds and carbohydrate on recombinant human erythropoietin structure.

We have isolated and characterized three anti-recombinant human erythropoietin (rHuEPO) monoclonal antibodies (MoAbs) that recognize nonoverlapping epitopes on rHuEPO. Anti-EPO MoAb D11 neutralizes rHuEPO activity whereas MoAbs F12 and 9G8A do not. This suggests that D11 may bind to the rHuEPO active site. MoAbs F12 and D11 recognize conformation dependent epitopes whereas 9G8A does not. Immunoassays were developed for each monoclonal. The 9G8A immunoassay was novel and useful because immunoreactivity increased when rHuEPO was denatured. Disruption of disulfide bonds or removal of carbohydrate increased 9G8A immunoreactivity, which suggests that these elements are important for rHuEPO structure or stability.