Generation of Recombinant Immunotoxin:

Recombinant immunotoxins are engineered proteins that combine the selectivity of antibody with the cell-killing potency of toxins. For their production, recombinant single-chain antibodies, also known as single-chain variable fragments (scFv), are produced through rDNA technology. These scFv consist of the variable regions of the heavy (VH) and light (VL) chains of immunoglobulins, linked by a short flexible peptide linker. The scFv can be conveniently produced in bacteria as it can be encoded by a single gene with genetic manipulation.

During production, scFv that specifically binds to the target antigen on the surface of cancer cells are designed. Then, a toxin fragment that can effectively kill the target cells is selected, such as Pseudomonas exotoxin A (PE), Diphtheria toxin (DT), or ricin. The designed scFv with the toxin is finally fused with a linker, which allows for proper folding and activity of both components.

Need for Immunotoxin:

There is a need for generation of immunotoxins as they serve as rationally engineered protein agents, often anti-cancer agents. They are designed to deliver toxins to specific cellular targets, ensuring targeted cell killing while minimizing damage to healthy cells.

Mechanism of Action:

The engineered protein uses the antibody part for selectivity, targeting the cancer cells displaying their antigens. Upon binding, the immunotoxin gets internalized into the target cell. The toxin part gets released from the endosome and effectively kills the cells.