Direct radiolabeling of antibody against stage specific embryonic antigen for diagnostic imaging
AssigneeRhomed Incorporated
InventorBuck A. Rhodes
Life of this patent
Estimating the term…
Abstract
Antibody against stage specific embryonic antigen-1 is radiolabeled by direct means with a radionuclide for use in detection of occult abscess and inflammation. Radiolabeling is accomplished by partial reduction of the disulfide bonds of the antibody using Sn(II), or using other reducing agents followed by the addition of Sn(II), removal of excess reducing agent and reduction by-products, and addition of a specified amount of radionuclide reducing agent, such as stannous tartrate. The resulting product may be store frozen or lyophilized, with radiolabeling accomplished by the addition of the radionuclide.
Claims20
A method of radiolabeling antibody against stage specific embryonic antigen-1 with a radionuclide to obtain stable labeling, comprising the steps of:
- a) incubating the antibody against stage specific embryonic antigen-1 with a Sn (II) agent, the period of incubation being sufficient to reduce available disulfide bonds to thiolate groups and allow formation of Sn (II)-containing and sulfur-containing complexes, while preventing excessive fragmentation of the antibody;
- b) purifying the reduced antibody to remove uncomplexed Sn (II) agents and other impurities yet retaining Sn (II) in a sufficient amount to reduce the radionuclide and not generate significant radio-chemical impurities, the radionuclide to be added in a subsequent step;
- and
- c) radiolabeling the purified antibody with the Sn (II)-containing and sulfur-containing complexes by adding the radionuclide, whereby the Sn (II) agent reduces the radionuclide and the reduced radionuclide forms radionuclide-containing and sulfur-containing complexes.
A method of producing reduced oxidation resistant intact antibody against stage specific embryonic antigen-1 for subsequent labeling with a radionuclide to obtain stable labeling, comprising the ordered steps of:
- a) incubating the intact antibody against stage specific embryonic antigen-1 with a first reducing agent, the period of incubation being sufficient to reduce available disulfide bonds to thiolate groups while preventing excessive fragmentation of the antibody;
- b) adding a source of first Sn (II) agent to the reduced intact antibody in a sufficient amount to form Sn (II)-containing and sulfur=containing complexes, resulting in formation of complexes between sulfur and Sn (II) which protect against subsequent reoxidation prior to purification and radiolabeling, the reduced intact antibody to purified in a subsequent step, and the radionuclide to be added in a subsequent step;
- c) purifying the rescued intact antibody to substantially remove the first reducing agent and impurities;
- d) freezing the purified reduced intact antibody containing Sn (II)-containing and sulfur-containing complexes in a vial, whereby the frozen purified reduced antibody containing Sn(II)-containing and sulfur-containing complexes can be maintained for an indefinite period before radiolabeling by the addition of the radionuclide;
- and
- e) radiolabeling the purified reduced intact antibody by adding the radionuclide, whereby the complexed first Sn(II) agent reduces the radionuclide and the reduced radionuclide and reduced antibody form stable radionuclide-containing and sulfur-containing complexes.
The method of claim 18 wherein 85 percent or more of the radionuclide is strongly bonded to the antibody.
Dependencies are inferred from the claim text.