zap-conjugates

Sawada R, Sun SM, Wu X, Hong F, Ragupathi G, Livingston PO, Scholz WW (2011) Human monoclonal antibodies to Sialyl-Lewisa (CA19.9) with potent CDC, ADCC, and antitumor activity. Clin Cancer Res 17(5):1024-1032. doi: 10.1158/1078-0432.CCR-10-2640

Summary: In this work the authors investigated the use of a carbohydrate antigen, sialyl-Lewisa (CA19.9), as a target for cancer therapeutics. Human monoclonal antibodies were generated against CA19.9 and characterized using ELISA and flow cytometry. To assess internalization one antibody, 5B1, was combined with Hum-ZAP (Cat. #IT-22) and applied to CA19.9-expressing BxPC3 cells. The cytotoxicity of the 5B1-Hum- ZAP complex indicates that CA19.9 may be a target for cancer therapy.

Related Products: Hum-ZAP (Cat. #IT-22)

Q: When we contacted you to find out more about having a custom saporin conjugation performed with our primary antibody, you recommended that we use the ATS secondary conjugate system to determine that our antibody was specific to the population we want to eliminate. We looked more at the website, and it seems that we are supposed to start with Anti-M-ZAP, Cat. #IT-30 (our primary Ab is a mouse IgM), and use the Mouse IgM-SAP, Cat. #IT-41 for control. Is this correct?

A: If your primary antibody is a mouse IgM, then you are correct that Anti-M-ZAP (Cat# IT-30) is the appropriate secondary conjugate to use. As for control conjugates, the best control would be a secondary conjugate using an IgM isotype control mixed with Anti-M-ZAP. An alternative would be to use Goat IgG-SAP (Cat# IT-19) made with normal goat IgG that mimics Anti-M-ZAP without the specific affinity for mouse IgM.

Once you determine you need a direct conjugate made between your mouse IgM primary antibody and saporin, then you would want to use the Mouse IgM-SAP (Cat# IT-41) as a control toxin just as you use your direct conjugate.

Related: ZAP Conjugates, Control Conjugates, Custom Conjugates

Yang MY, Chaudhary A, Seaman S, Dunty J, Stevens J, Elzarrad MK, Frankel AE, St Croix B (2011) The cell surface structure of tumor endothelial marker 8 (TEM8) is regulated by the actin cytoskeleton. Biochim Biophys Acta 1813(1):39-49. doi: 10.1016/j.bbamcr.2010.11.013

Summary: Tumor endothelial marker 8 (TEM8) is a cell surface protein that is up-regulated on tumor blood vessels. Overexpression of this protein, however, produces a form that is not recognized by the SB5 monoclonal antibody used to bind TEM8. While cells expressing normal levels of TEM8 were killed by an application of biotinylated SB5 plus either 1 nM or 10 nM streptavidin-ZAP (Cat. #IT-27), cells overexpressing the protein did not bind the immunotoxin. Understanding the structural differences between the two forms of TEM8 will help in the design of therapeutic antibodies against these tumor cells.

Related Products: Streptavidin-ZAP (Cat. #IT-27)

Quadros EV, Nakayama Y, Sequeira JM (2010) Targeted delivery of saporin toxin by monoclonal antibody to the transcobalamin receptor, TCblR/CD320. Mol Cancer Ther 9(11):3033-3040. doi: 10.1158/1535-7163.MCT-10-0513

Summary: Vitamin B12 is necessary for cell proliferation. Cancer cells display an increased expression of TCb1R, the receptor that facilitates the intake of B12. In order to evaluate the potential of using immunotoxins to eliminate cancer cells expressing TCb1R the authors performed a series of in vitro experiments using their monoclonal antibodies plus Mab-ZAP (Cat. #IT-04). The results indicate that this is a viable therapeutic model that causes minimal peripheral damage.

Related Products: Mab-ZAP (Cat. #IT-04)

Kuroda K, Liu H, Kim S, Guo M, Navarro V, Bander NH (2010) Saporin toxin-conjugated monoclonal antibody targeting prostate-specific membrane antigen has potent anticancer activity. Prostate 70(12):1286-1294. doi: 10.1002/pros.21164

Summary: Current treatments for prostate cancer are only moderately effective. In this work the authors examined the cytotoxic efficacy of an anti-prostate-specific membrane antigen (PMSA) antibody conjugated to saporin on PMSA-positive cell lines. hJ591, a humanized anti-PMSA antibody, was biotinylated and combined with streptavidin-ZAP (Cat. #IT-27). The hJ591-streptavidin-ZAP complex was specifically cytotoxic to PMSA-positive cell lines, and had anti-cancer activity in a xenograft model. This work demonstrates the anti-cancer potential of targeting PMSA.

Related Products: Streptavidin-ZAP (Cat. #IT-27)

Hovinga KE, Shimizu F, Wang R, Panagiotakos G, Van Der Heijden M, Moayedpardazi H, Correia AS, Soulet D, Major T, Menon J, Tabar V (2010) Inhibition of notch signaling in glioblastoma targets cancer stem cells via an endothelial cell intermediate. Stem Cells 28:1019-1029. doi: 10.1002/stem.429 PMID: 20506127

Summary: The antibody CD105 (1:1,000) was incubated with Mab-ZAP, to allow binding and formation of a CD105 antibody-saporin complex, which was added to explants or to a human cerebral microvessel endothelial cell line as control.  CD105 antibody was also incubated with a Goat-IgG-SAP for control  that does not bind CD105.  The conjugates were injected into the explant under a dissecting microscope after gently incising the explant surface for better access.

Related Products: Mab-ZAP (Cat. #IT-04), Goat IgG-SAP (Cat. #IT-19)

Vincent BG, Young EF, Buntzman AS, Stevens R, Kepler TB, Tisch RM, Frelinger JA, Hess PR (2010) Toxin-coupled MHC class I tetramers can specifically ablate autoreactive CD8+ T cells and delay diabetes in nonobese diabetic mice. J Immunol 184(8):4196-4204. doi: 10.4049/jimmunol.0903931

Summary: MHC class I tetramers have been used to identify antigen-specific cells. In this work the authors used a biotinylated tetramer in conjunction with streptavidin-ZAP (Cat. #IT-27) to eliminate a specific subset of reactive T cells associated with islets in vivo. NOD mice received three 4.36 µg intravenous injections of the tetramer/saporin complex over 12 days. The onset of type I diabetes in the treated mice was significantly delayed.

Related Products: Streptavidin-ZAP (Cat. #IT-27)

Ariizumi K, Akiyoshi H, Chung JS, Tomiharu M, Cruz Jr PD (2010) Featured Article: Depletion of syndecan-4+ T lymphocytes by saporin-conjugated DC-HIL alleviates T cell-mediated imflammatory disease. Targeting Trends 11(2)

Related Products: Streptavidin-ZAP (Cat. #IT-27)

Read the featured article in Targeting Trends.

See Also:

• Akiyoshi H et al. Depleting Syndecan-4+ T Lymphocytes Using Toxin-Bearing Dendritic Cell-Associated Heparan Sulfate Proteoglycan-Dependent Integrin Ligand: A New Opportunity for Treating Activated T Cell-Driven Disease. J Immunol 184:3554-3561, 2010.

Akiyoshi H, Chung JS, Tomihari M, Cruz PD, Jr., Ariizumi K (2010) Depleting syndecan-4+ T lymphocytes using toxin-bearing dendritic cell-associated heparan sulfate proteoglycan-dependent integrin ligand: A new opportunity for treating activated T cell-driven disease. J Immunol 184:3554-3561. doi: 10.4049/jimmunol.0903250

Summary: The dendritic cell-associated heparin sulfate proteoglycan-dependent integrin ligand (DC-HIL) exclusively associates with syndecan-4 (SD-4), which is expressed on some activated T cells. The authors biotinylated DC-HIL and combined it with streptavidin-ZAP (Cat. #IT-27). This complex was then applied to resting or activated T cells in culture at a concentration of 10 µg/ml. Only activated T cells were bound and eliminated.

Related Products: Streptavidin-ZAP (Cat. #IT-27)

Read the featured article in Targeting Trends.

Berg K, Weyergang A, Prasmickaite L, Bonsted A, Hogset A, Strand MT, Wagner E, Selbo PK (2010) Photochemical internalization (PCI): a technology for drug delivery. (eds. Gomer C). In: Photodynamic Therapy. Methods in Molecular Biology. 635:133-145. Humana Press, Totowa, NJ. doi: 10.1007/978-1-60761-697-9_10

Summary: This review discusses photochemical internalization (PCI), which is a method used to overcome some of the intracellular barriers to introducing molecules into cancer cells. Some difficulties for such therapies include a low rate of release from endocytic vescicles and degradation of the therapeutic molecule by lysosomal enzymes. The use of streptavidin-ZAP (Cat. #IT-27) with a biotinylated anti-EGF receptor antibody is discussed.

Related Products: Streptavidin-ZAP (Cat. #IT-27)

See Also:

• Yip WL et al. Targeted delivery and enhanced cytotoxicity of cetuximab-saporin by photochemical internalization in EGFR-positive cancer cells. Mol Pharm 4(2):241-251, 2007.