Method of preparing diphtheria immunotoxins
AssigneesThe United States of America, as represented by the Secretary, Department of Health and Human Services, Cetus Corporation
InventorsVirginia G. Johnson, Larry Greenfield, Richard J. Youle, Walter Laird
Life of this patent
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Abstract
A potent and specific immunotoxin is prepared by coupling an inactivated diphteria toxin to a binding moiety such as a monoclonal antibody or transferrin. The immunotoxins are specific for human tumors and leukemias and are indistinguishable in cell toxicity from that of the native toxin linked to the binding domain without the toxicity to other cells. The immunotoxin is useful in treating graft versus host disease as well as selectively killing tumor cells, such as medulloblastoma and glioblastoma cells.
Claims14
A method of preparing an immunotoxin comprising:
- linking an inactivated diphtheria toxin in which the native binding site has been inactivated, said inactivated diphtheria toxin being selected from the group consisting of CRM102, CRM103, and CRM107 to an ester to form a linked toxin;
- reducing a binding moiety, said binding moiety being a moiety which binds to a specific receptor;
- mixing the linked toxin with reduced binding moiety and incubating the mixture;
- and
- separating immunotoxins formed from unconjugated binding moiety and toxin.
A method of preparing an immunotoxin comprising:
- linking an inactivated diphtheria toxin, in which the native binding site within the carboxyl 17-kDa portion of the B chain of the diphtheria toxin has been inactivated without inactivation of the translocation function of the B chain, to an ester;
- reducing a binding moiety, said binding moiety being a moiety which binds to a specific receptor;
- mixing the linked toxin with reduced binding moiety and incubating the mixture;
- and
- separating immunotoxins formed from unconjugated binding moiety and toxin.
Dependencies are inferred from the claim text.