Procedure for the covalent bonding of ligands for the preparation of immunochemical reagents for use in homogeneous immunoanalyses using microparticles (MPs) and its application to the measurement of ferritin and the soluble receptor for transferrin in blood serum or plasma

摘要

Procedure for the covalent bonding of ligands for the preparation of immunochemical reagents for use in homogeneous immunoanalyses using microparticles (MPs) and its application to the measurement of ferritin and the soluble receptor for transferrin in blood serum or plasma. The procedure consists of a reagent for measuring substances in biological samples that includes the use of microparticles MPs in an aqueous suspension covered with an antibody Ac by means of a ligand-contraligand bridge. In this reagent the MPs have a contraligand such as avidin or streptavidin fixed on their surface and the specific antibodies are marked with a ligand such as biotin. In addition, the present invention describes a specific procedure for the covalent bonding of ligands on the Fc fraction of the antibodies that permits a spatial arrangement of them on the MPs that is very favourable to immunoaggregation. As a result of this spatial arrangement, the number of active antibodies is increased which therefore reduces the quantity of antibody needed to prepare the reagents. Also, and owing to this favourable spatial arrangement, non-specific reactions due to the rheumatoid factor are eliminated and the stability of the reagents is improved. The invention is applicable to the evaluation of the state of iron reserves by turbidimetric/nephalometric determination of the ferritin and the transfer receptors in blood serum or plasma.