Antibody therapy has become an important part of the treatment of malignant diseases. Antibodies can block tumor growth factors or their receptors, activate immune attacks on tumors, and are used to deliver payloads such as radioisotopes, cytotoxic drugs, or toxins. Recombinant immunotoxin is a new class of anti-tumor drugs. In general, it is an antibody-toxin chimeric molecule that kills cancer cells by binding the antibody portion to the surface antigen, internalizing and delivering the toxin portion to the cytosol. In the cytoplasm, toxins catalyze the inhibition of key cell functions and cause cell death. Creative Biolabs provides a comprehensive list of RITs products (not limited to antibody-based RITs) for our world-wide customers. Our RITs products are mainly divided into the following categories:
● Antibody-based RITs
● Ligand-based RITs
● Peptide-based RITs
● Bispecific RITs
The Antibody Moiety
The antibody portion of the chimera targets antigens that are preferentially expressed on the surface of cancer cells. The antibodies used are generated by monoclonal antibody technology. Since antibodies have a large molecular weight, it is difficult to penetrate solid cancer tumors with severely restricted blood supply. As a solution, immunotoxins that use only the protein-binding portion of the antibody (called the variable region) can be produced. Generally, Fab fragments, single-chain Fv (scFv) are currently the most popular methods. In scFv, the variable domains (VH and VL) and the flexible polypeptide linker are stably linked together. Smaller antibody fragments (such as Fab or scFv) exhibit better pharmacokinetics and also provide complete binding specificity because the antigen binding surface has not changed.
The Toxin Moiety
The toxins used in immunotoxin constructs originate from bacteria, fungi and plants, and exert their greatest effect by inhibiting protein synthesis. Bacterial toxins commonly used in immunotoxins include diphtheria toxin (DT) and toxin produced by Pseudomonas exotoxin (PE). Plant toxins used in immunotoxins include ricin A chain (RTA), ribosome inactivating protein (RIP) gelatin protein, pokeweed antiviral protein and dodecane. Because it is an enzyme, a toxin molecule can act on many substrate molecules and have a destructive effect on cells. Toxins such as diphtheria toxin (DT) and pseudomonas exotoxin (PE) prevent protein synthesis by affecting elongation factor 2 (EF-2). However, in order to be effective, the immunotoxin must be internalized and transferred to the appropriate intracellular compartment to transport the attached toxin into the cytoplasm. The antibody targeting portion and the toxin are connected by a cross-linking agent, which is stable outside the cell but unstable inside the cell, so the toxin can play a role in the cytoplasm.
Please browse the following RITs product list to find the right product for you. Or you can contact us to ask for a customized solution tailored to your specific needs.
