Competitive inhibition ELISAs confirm polyreactive binding patterns of human MALT lymphoma antibodies. (A-C) Three representative competition ELISAs performed as described in the legend to Figure 4 are shown and demonstrate the ability of different soluble targets to inhibit the binding of the recombinant antibody of interest (5, 4, and 1; used at 10 μg/mL) to solid-phase antigens. BSA did not block binding of Abs 5 and 4 even at 100× excess concentrations (A-B right panels). Error bars represent SEM.