Abstract: A method of isolating a protein from a mixture containing the protein, the method including providing an antibody immobilized on a solid support, which antibody is reactive with the protein complexed with a ligand and substantially unreactive with the protein not complexed with the ligand; contacting the mixture, in the presence of the ligand, with the immobilized antibody to bind the protein, complexed with the ligand, to the immobilized antibody to form an immune complex; and contacting the immune complex with a compound having a binding affinity for the ligand higher than the binding affinity of the protein for the ligand, to release the protein from the immobilized antibody.

Abstract: Antibodies which form immune complexes with human native prothrombin only, in the presence of mixtures of human native prothrombin and human abnormal prothrombin as well as antibodies which form antibody antigen complexes with human abnormal prothrombin in the presence of such mixtures have been obtained. Immunoassay techniques are used for qualitative and quantitative determinations of these antigens in human plasma or serum. Unique methods of obtaining the antibodies are described including obtaining antibodies to native prothrombin by dissociation of antigen antibody complexes formed in the presence of calcium ions with a material having a greater affinity constant for binding with calcium ions than does prothrombin. Dissociation of the complex in this manner yields human native prothrombin antibodies which are specific and non-reactive with human abnormal prothrombin.

Abstract: An antibody reactive with activated human platelets, and substantially unreactive with resting human platelets, with the azurophilic granules of monocytes, and with granulocytes.

Abstract: Antibodies which form immune complexes with human native prothrombin only, in the presence of mixtures of human native prothrombin and human abnormal prothrombin as well as antibodies which form antibody antigen complexes with human abnormal prothrombin in the presence of such mixtures have been obtained. Immunoassay techniques are used for qualitative and quantitative determinations of these antigens in human plasma or serum. Unique methods of obtaining the antibodies are described including obtaining antibodies to native prothrombin by dissociation of antigen antibody complexes formed in the presence of calcium ions with a material having a greater affinity constant for binding with calcium ions than does prothrombin. Dissociation of the complex in this manner yields human native prothrombin antibodies which are specific and non-reactive with human abnormal prothrombin.