A multiwell lectin-binding assay using lotus tetragonolobus for measuring different glycosylated forms of haptoglobin.

Using the fucose-specific lectin, Lotus tetragonolobus, we recently isolated abnormally-glycosylated forms of haptoglobin (FHp) that are useful for monitoring cancer patients and for detecting active disease in rheumatoid arthritis. FHp is detected by electrophoresis and silver staining. In order to use FHp clinically, a better assay is required. A lectin-binding assay (LBA) is described, in which FHp is captured by lotus bound to multi-well plates, and the amount captured is measured by an enzyme-labelled antibody system. The LBA results correlate with those obtained with electrophoresis. The method also gives good precision and low background values. In the presence of 1 mol/l fucose the bound-FHp was reduced by between 60-100%. This confirms that the method is detecting abnormally-fucosylated forms of haptoglobin. This approach opens up exciting possibilities for investigating large numbers of pathological sera and it suggests that other combinations of lectin and antibody may be worth investigating in the future.