Streptavidin-ZAP converts biotinylated materials into targeted toxins. Streptavidin is a tetrameric protein (molecular weight 53 kDa in its recombinant form), with each subunit able to bind a single biotin molecule. The bond between streptavidin and biotin is rapid and essentially non-reversible, unaffected by most extremes of pH, organic solvents, and denaturing reagents. It is the strongest known noncovalent biological interaction (Ka = 1015 M-1) between protein and ligand. The streptavidin used to make Streptavidin-ZAP contains no carbohydrate group and has a neutral isoelectric point, which therefore reduces the nonspecific binding as compared to avidin. A variety of molecules, including lectins, proteins, and antibodies, can be biotinylated and reacted with streptavidin-labeled probes or other detection reagents for use in biological assays.
Streptavidin-ZAP is a chemical conjugate of streptavidin and the ribosome-inactivating protein, saporin. It converts biotinylated materials into targeted toxins.
Summary: This manuscript describes the myriad of ways Streptavidin-ZAP is used and how this technology supports the scientific process of ‘Molecular Surgery’ and progress in research and drug development. Insights from publications and research performed using Streptavidin-ZAP and its impact on academia and industry for research and drug development are presented.
Ancheta LR, Shramm PA, Bouajram R, Higgins D, Lappi DA (2022) Saporin as a commercial reagent: its uses and unexpected impacts in the biological sciences-tools from the plant kingdom. Toxins (Basel) 14(3):184. doi: 10.3390/toxins14030184
Objective: To further investigate and develop the utility of CD45-SAP and CD117-SAP, in combination with immunosuppression, in murine transplant models using i.v. administration in an allogeneic minor mismatch transplant model (Balb/c donor into DBA/2 recipients).
Summary: CD45-SAP or CD117-SAP in combination with immunosuppressants (30Fll and post-transplant Cytoxan) enabled >85% peripheral donor chimerism at 12 weeks post-transplantation. CD45-SAP and CD117-SAP were more effective at conditioning versus 2Gy TBI or pretransplant Cytoxan.
Usage: CD45-SAP (1.9 mg/kg, iv) and CD117-SAP (1mg/kg, iv) in an allogeneic minor mismatch transplant model (Balb/c donor into DBA/2 recipients).
Van Hentenryck M, Li Z, Murphy PM, Czechowicz A (2022) Antibody-based preparative regimens for cell, tissue and organ transplantation. (eds. 162). OBM Transplantation 6(3):162. doi: 10.21926/obm.transplant.2203162
Objective: Provide a review of progress in the use of antibodies to support cell and tissue transplantation with a particular focus on induction of donor-specific tolerance for solid organ transplantation.
Summary: Antibody-based conditioning to prepare the recipient is a promising approach towards achieving transplant tolerance in both hematopoietic and solid organ transplant settings.
Usage: To enhance HSC depletion while avoiding bystander toxicity (neutropenia, lymphopenia, and thrombocytopenia) caused by CD45-radioimmunotherapy, Palchaudhuri et al. developed a saporin-based CD45 (CD45-SAP) immunotoxin using a biotinylated antibody and Streptavidin-ZAP.
Kohls M (2006) Evaluate Potential Targeting Molecules. Nature Methods
Summary: Targeted toxins -- targeting agents conjugated to saporin -- are widely used to eliminate specific cell populations both in vitro and in vivo. For these molecules to be effective, it is vital that the targeting component of the conjugate specifically binds the cells of interest. A secondary conjugate, Streptavidin-ZAP, has been created by attaching the toxin saporin to streptavidin. The user can combine primary biotinylated material with Streptavidin-ZAP to quickly and economically screen potential targeting molecules for internalization and specificity. Once the appropriate targeting molecule is identified, a direct conjugation with saporin can be performed.