Antibodies and antibody-based assays for hexavalent uranium Original Research Article

Three hybridoma cell lines (8A11, 12F6 and 10A3) have been generated that synthesize and secrete monoclonal antibodies that bind tightly and specifically to UO22+ complexed to 1,10-phenanthroline-2,9-dicarboxylic acid (DCP). These antibodies showed differences in their ionic strength and pH dependencies. The three antibodies have been used to construct competitive immunoassays for soluble UO22+. In a competitive microwell immunoassay format, the antibodies measured soluble UO22+ at concentrations ranging from 0.3 to 10 μM (9.5–2400 ppb). Metal ion specificity of the 8A11 antibody was determined by the individual addition of 1 ppm of 19 different atomic absorption-grade metals (Cu(II), Al(III), Mo(VI), Hg(II), Cd(II), Zn(II), Ni(II), Co(II), Pb(II), Mn(II), Sr(II), Ca(II), Au(III), In(III), Fe(III), Ti(III), Yt(III), Pr(III), or Er(III)) to the competitive microwell assay. The addition of these metals had no effect on the response of the immunoassay to soluble UO22+. In a competitive assay format that utilized the KinExA automated immunoassay instrument, the 8A11 antibody-based assay was linear with UO22+ concentrations from 1 to 5 nM (0.24–1.2 ppb).