Pretargeting Strategy Using Avidin-biotin System

Small amounts of monoclonal antibodies bind to tumors, and monoclonal antibodies bound to cytotoxic agents continue to circulate in the bloodstream and normal tissues. Biotin can be conjugated to monoclonal antibodies, enhancing the binding site and delivering monoclonal antibodies. Designing a pre-targeting strategy needs to take into account the following factors: tumor imaging contrast and tumor therapeutic index (TI), antibody immunogenicity and specificity, applicability of radionuclides, and ease of use in the clinic. Pretargeting strategies can be widely applied to different tumor targets, tumor types or radionuclides. The multifunctionality of pre-targeting provides great application potential for the diagnosis and treatment of tumors, but its development still faces great challenges. Cancer diagnosis and experimental therapy have been performed using radiolabeled monoclonal antibodies with encouraging results.

The Services

The related services we can provide include but are not limited to:

• Radioactive labeling of materials
• Pretargeted radioimmunoimaging and biodistribution studies
• Pre-targeted radioimmunotherapy studies
• Statistical analysis
• Quality control of labeled compounds
• Pretargeted radioimmunoimaging

Disadvantages of pretargeting using the avidin-biotin system

A disadvantage of pretargeting techniques is repeated injections at defined time intervals. The immunogenicity of avidin is another disadvantage of pretargeting techniques using these proteins. Internalization of the antigen-antibody complex renders the radiolabel inaccessible to the target molecule for antibody delivery.

Pre-targeting strategy

Pretargeting strategies can play an important role in addressing the high toxicity of RIT. Key to pretargeting is the concept of decoupling the targeting vector from the cytotoxic agent and administering it separately. Tumor targeting with slow pharmacokinetic drugs is a major challenge in nuclear imaging and targeted radionuclide therapy because they often result in low imaging contrast and high radiation dose to healthy tissue.

Current research

Biotinylated antibodies or streptavidin-conjugated antibodies were used as antibody conjugates. Streptavidin or biotin is labeled as a carrier for the radionuclide. Current pretargeting protocols involving the avidin-biotin system are as follows:

• Antibody-conjugates
• Radiolabels
• Clearing agents
• Animal experiments
• Clinical applications

Applications of the avidin-biotin system

• Biotin and Diagnostics: Labeled Avidin Biotin (LAB), Bridged Avidin-Biotin (BRAB) and Avidin-Biotin-Peroxidase Complex (ABC)
• Biotin and affinity chromatography: The biotin-avidin system can be combined with affinity chromatography to greatly improve the purity of purified proteins
• Biotin and positioning observation: Avidin-labeled probe positioning is beneficial to the positioning of trace antigens (or antibodies) at the cellular or subcellular level.
• Biotin and gene probes: Biotin-labeled phosphate bases synthesize gene probes, avoiding the possible damage caused by radioactive substances during the experiment.

Advantages of the avidin-biotin system

• High sensitivity
• High specificity
• High stability
• Universal adaptation

Alfa Chemistry has a professional laboratory, has independent research and development capabilities, has accumulated rich knowledge, and has the ability to provide customers with satisfactory services. If you are interested in our services, please contact us immediately.

References:

1. Péter. H.; et al. Functionalized liposomes loaded with siRNAs targeting ion channels in effector memory T cells as a potential therapy for autoimmunity. Biomaterials. 2013. 34(38): 10249-10257.
2. Paganelli. G.; et al. Pretargeting of carcinomas with the avidin-biotin system. Int J Biol Markers. 1993, 8(3):155-159.

※ It should be noted that our service is only used for research, not for clinical use.