zap-conjugates

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.

Q: Concerning Hum-ZAP (Cat. #IT-22) and Rat-ZAP (Cat. #IT-26), are they monovalent or bivalent to their target immunoglobulins?

A: The secondary conjugates Hum-ZAP and Rat-ZAP are, in fact, bivalent and so do have the theoretical possibility of causing internalization when the primary would not – a false positive. In fact, we have never heard of this happening, mainly because the theoretical situation is difficult to put into practice – probably things get a little bulky on the cell surface.

Our idea is that the secondary conjugates are meant for large-scale screening in a very cost-effective manner, and upon identification of a positive, that primary antibody can be biotinylated and tested in vivo with streptavidin-ZAP (Cat. #IT-27). Streptavidin-ZAP can also cause oligomerization, but it’s used at equimolar amounts to the primary antibody, so that may not happen to an appreciable amount. However, the best method is to have a primary immunotoxin constructed through custom synthesis, in which saporin is directly coupled to the targeting agent.

Related: ZAP Conjugates

Penaloza-MacMaster P, Masopust D, Ahmed R (2009) T-cell reconstitution without T-cell immunopathology in two models of T-cell-mediated tissue destruction. Immunology 128:164-171. doi: 10.1111/j.1365-2567.2009.03080.x

Summary: Although antigen-specific T cells are vital to adaptive immune responses, they also contribute to a variety of diseases. In this work the authors examined the possibility of selectively removing epitope-specific T cells while preserving immune function. Biotinylated MHC class I tetramers were combined with streptavidin-ZAP (Cat. #IT-27) and used in a mouse transferable T-cell-dependent neurological disease model. This technique resulted in a dramatic reduction in targeted antigen specific T cells with no observable bystander toxicity.

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

Q: We were wondering how an IgM primary antibody might work in a Mab-ZAP assay. I realize that the conjugated antibody is an anti-IgG whole molecule antibody. However there may well be aspects/epitopes shared in common between IgG and IgM that might render an IgM primary useful with the Mab-ZAP reagent… or not? Has anyone looked at this with your products?

A: We do believe, but have not confirmed, that you will see a cross-reactivity, but at a lower level. We do sell a second immunotoxin for IgM’s, Anti-M-ZAP (Cat. #IT-30) which is made from a goat anti-murine IgM.

Related: Mab-ZAP (Cat. #IT-04), Anti-M-ZAP (Cat. #IT-30)

Hess PR, Buntzman AS, Murray SL, Young EF, Frelinger JA (2009) Featured Article: Selective deletion of CD8+ T cells by saporin-coupled MHC class I tetramers. Targeting Trends 10(1)

Related Products: Streptavidin-ZAP (Cat. #IT-27), Saporin Goat Polyclonal, affinity-purified FITC-labeled (Cat. #AB-15APFL)

Read the featured article in Targeting Trends.

See Also:

• Hess PR et al. Selective deletion of antigen-specific CD8+ T cells by MHC class I tetramers coupled to the type I ribosome-inactivating protein saporin. Blood 109:3300-3307, 2007.

Rouleau C, Curiel M, Weber W, Smale R, Kurtzberg L, Mascarello J, Berger C, Wallar G, Bagley R, Honma N, Hasegawa K, Ishida I, Kataoka S, Thurberg BL, Mehraein K, Horten B, Miller G, Teicher BA (2008) Endosialin protein expression and therapeutic target potential in human solid tumors: sarcoma versus carcinoma. Clin Cancer Res 14:7223-7236. doi: 10.1158/1078-0432.CCR-08-0499

Summary: Endosialin is an antigen expressed in many human cancer cell lines. As part of a wide-ranging study investigating clinical specimens, cell culture, and animal models, this group used Hum-ZAP (Cat. #IT-22) combined with a humanized anti-endosialin antibody in cell proliferation assays. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The anti-endosialin antibody and Hum-ZAP were incubated together in equimolar concentrations then applied to cells in culture. Various cancers, including synovial sarcoma, fibrosarcoma, and osteosarcoma among others, were found to express endosialin.

Related Products: Hum-ZAP (Cat. #IT-22), Mouse IgG-SAP (Cat. #IT-18)

Zhao XY, Liu HL, Liu B, Willuda J, Siemeister G, Mahmoudi M, Dinter H (2008) Tomoregulin internalization confers selective cytotoxicity of immunotoxins on prostate cancer cells. Transl Oncol 1:102-109. doi: 10.1593/tlo.08124

Summary: Tomoregulin is a type 1 transmembrane protein with a short cytoplasmic tail, and is found in the brain and prostate. After confirming cell surface localization by flow cytometry, and determining expression levels by whole-cell binding assays, the authors evaluated the use of tomoregulin as a target for immunotoxin therapy. Cells transfected with tomoregulin were treated with anti-tomoregulin + Mab-ZAP (IC50 = 160 pM; Cat. #IT-04) in vitro. The results demonstrate the potential for tomoregulin in prostate cancer treatment.

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