FIBRINOGEN AS A FERRITIN-BINDING PROTEIN IN HORSE PLASMA

Lower apparent concentrations of ferritin were observed in horse plasm a than in serum using the enzyme-linked immunosorbent assay (ELISA). H owever, the ferritin concentrations in plasma and serum were increased to the same level on heating the samples at 75-degrees-C for 15 min. These results suggest that horse plasma has specific ferritin-binding protein(s) which inhibit(s) the ferritin assay. The apparent ferritin concentrations in horse serum were markedly decreased by adding horse fibrinogen to the serum. It was also found that fibrinogen bound to sp leen ferritin and inhibited the immunoassay of this protein. From thes e results, it was concluded that horse fibrinogen is one of the ferrit in-binding proteins which inhibit the immunoassay of horse ferritin.