ABSTRACT
Department of Biochemistry, Indian Institute of Science, Bangalore, India Immunotherapy is fast emerging as one of the leading modes of treatment of cancer, in combination with chemotherapy and radiation. Use of immunotoxins, proteins bearing a cell-surface receptor-specific antibody conjugated to a toxin, is expected to enhance the efficacy of cancer treatment. Of the numerous known molecules that inhibit translation, abrin, isolated from the Abrus precatorius plant, is one of the most potent ones but has not been exploited in designing immunotoxins. Abrin, a type II ribosome inactivating protein, has a catalytic efficiency higher than any other toxin belonging to this class of proteins. To overcome the drawbacks of the holotoxin that enters any and every cell, and also increase the specificity of the conjugate, we used the recombinant A chain of abrin to conjugate to antibodies raised against the human Gonadotropin releasing hormone receptor. The conjugate inhibited translation and also induced apoptosis in cells expressing the receptor but not in cells lacking the receptor. Read More…