| 摘要 |
The present invention provides a plant holotoxin comprising 1 alpha , 1 beta and 2 gamma subdomains and having a modification in a lectin binding site in each of the 1 alpha , 1 beta and 2 gamma subdomains. In addition, the present invention provides a plant holotoxin fusion protein comprising a moiety consisting of a plant holotoxin comprising 1 alpha , 1 beta and 2 gamma subdomains and having a modification in a lectin binding site in each of the 1 alpha , 1 beta and 2 gamma subdomains and a moiety consisting of a ligand specific for a cell surface receptor. Furthermore, a method of constructing a ricin fusion protein immunotoxin is provided, comprising expressing the nucleic acid in a vector in a eukaryotic cell expression system to produce a fusion protein; isolating and purifying the fusion protein; and contacting the fusion protein of with a ricin toxin A chain under conditions which permit the association the fusion protein with the ricin toxin A chain. In addition, the present invention provides a method of treating a cancer or an autoimmune disease in a patient diagnosed with a cancer or an autoimmune disease comprising constructing a ricin fusion protein immunotoxin, wherein the ligand is specific for a particular cell surface receptor present only on the surfaces of the cancer cells or on the surfaces of the cells causing the patient's autoimmune disease; and administering the ricin fusion protein immunotoxin in a pharmaceutically acceptable carrier to the patient, whereby the ricin fusion protein immunotoxin treats the patient's cancer or autoimmune disease. |
