zap-conjugates

Sims S, Bolinger B, Klenerman P (2015) Increasing inflationary T-cell responses following transient depletion of MCMV-specific memory T cells. Eur J Immunol 45:113-118. doi: 10.1002/eji.201445016

Summary: The standard CD8+ T-cell response to infection is a rapid proliferation followed by a reduction in number after the infection is cleared. Murine cytomegalovirus is an exception in that an infection generates a life-long latency with low-level sporadic replication. Immunodominant cells accumulate over time and stabilize at a high frequency. The authors examined a paradoxical boost following depletion of these cells with an M38 antibody attached to Streptavidin-ZAP (Cat. #IT-27). Mice were treated with 44 pM intraperitoneal injections. M38 is an epitope present on the effector CD8+ T cells. Following a significant depletion of cells, the population rebounded and reached a higher percentage of total CD8+ T-cells than before the depletion.

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

Q: I have been using your ZAP Antibody Internalization Kit. It is working well for me, but I can only test one antibody at a time. Do you offer the ZAP kit in larger sizes?

A: We do offer kits with sufficient components to test multiple antibody candidates. We offer “Z4” and “Z10” sizes of kits that include all of the same consumable components of the original ZAP kit in quantities sufficient to test 4 or 10 antibodies, respectively. While the included recommended protocol is identical to the original ZAP kit, the added materials provide an opportunity for the experienced researcher to streamline their experiment by testing multiple antibody candidates at one time.

Related Products: ZAP Conjugates

Ha K, Bidlingmaier S, Zhang Y, Su Y, Liu B (2014) High-content analysis of antibody phage-display library selection outputs identifies tumor selective macropinocytosis-dependent rapidly internalizing antibodies. Mol Cell Proteomics 13:3320-3331. doi: 10.1074/mcp.M114.039768

Summary: Macropinocytosis, the internalization of large endocytic vesicles called macropinosomes, is upregulated in Ras-transformed cancers. To date, large-scale antibody generation strategies have not incorporated a selection method for antibodies. In this work the authors demonstrate screening and validation of the antibodies that utilize the macropinosome pathway. One method used was to biotinylate the antibodies and combine them with Streptavidin-ZAP (Cat. #IT-27) at a 1:1 ratio. The conjugate was applied to cells in a concentration curve starting at 200 nM in order to demonstrate internalization and cell killing.

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

Bostad M, Kausberg M, Weyergang A, Olsen C, Berg K, Høgset A, Selbo P (2014) Light-triggered, efficient cytosolic release of IM7-saporin targeting the putative cancer stem cell marker CD44 by photochemical internalization. Mol Pharm 11:2764-2776. doi: 10.1021/mp500129t

Summary: CD44 is known as a common cancer stem cell (CSC) marker. Given that CSC’s seem to have the ability to resist many therapeutic agents, the authors investigated the use of photochemical internalization (PCI) while targeting CD44-expressing CSC’s. An immunotoxin was constructed by biotinylating a pan CD44 antibody and combining it with Streptavidin-ZAP (Cat. #IT-27) at a 4:1 biotinylated antibody to Streptavidin-ZAP molar ratio. Various cancer cell lines were incubated with the toxin at a concentration of 0.825 nM. The toxin showed specific cytotoxicity to CD44-expressing cell lines, demonstrating the efficacy of PCI in conjunction with targeted toxins to treat some cancers

Related Products: Streptavidin-ZAP (Cat. #IT-27), Anti-CD44-SAP (Cat. #IT-72)

Q: I ordered the Streptavidin-ZAP (Cat. #IT-27) and had my antibody biotinylated a couple of months ago. I am ready to begin the first round of experiments to determine the concentration needed for the secondary. How much of the biotinylated antibody should I put to combine with the streptavidin for intravitreal injections? Can you please send me a protocol for how to determine the ratio of primary to secondary?

A: Streptavidin-ZAP should be mixed with the biotinylated material at an equimolar concentration. The Streptavidin-ZAP you ordered should have included a data sheet which gives the protein concentration and molecular weight, which you would use to determine the molar concentration. We have a calculator page on our website which can help with this if needed.

Listed below is a publication using Streptavidin-ZAP combined with a biotinylated antibody being used in intravitreal injections. The reference describes in detail the quantities they tried. You can also browse references on our site to see how scientists use ATS products to accomplish their research goals and publish in respected journals.

References

1. Ren C et al. Direct retino-raphe projection alters serotonergic tone and affective behavior. Neuropsychopharmacology 38(7):1163-1175, 2013.

Alonso M, Gregorio J, Davidson M, Gonzalez J, Engleman E (2014) Depletion of inflammatory dendritic cells with anti-CD209 conjugated to saporin toxin. Immunol Res 58:374-377. doi: 10.1007/s12026-014-8511-6

Objective: To investigate a strategy that avoids monocyte intermediates to deplete inflammatory dendritic cells (DCs). Mice with an abundance of inflammatory DCs as a consequence of lipopolysaccharide exposure were treated with anti-CD209 antibody conjugated to saporin.

Summary: The results demonstrate depletion of CD209+ DCs. This strategy could prove useful for the targeted reduction of inflammatory DCs in disease.

Usage: Streptavidin-ZAP mixed with biotinylated Anti-CD209 was delivered i.v. to mice. Inflammatory DCs were markedly depleted.

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

Lund K, Bostad M, Skarpen E, Braunagel M, Krauss S, Duncan A, Hogset A, Selbo P (2014) The novel EpCAM-targeting monoclonal antibody 3-17I linked to saporin is highly cytotoxic after photochemical internalization in breast, pancreas and colon cancer cell lines. MAbs 6(4):1038-1050. doi: 10.4161/mabs.28207

Summary: The epithelial cell adhesion molecule (EpCAM) is an attractive diagnostic and therapeutic target for a wide range of human carcinomas. It has also been found on cancer stem cells, increasing the interest in targeting and eliminating cells that express it. The authors have created a monoclonal antibody that binds EpCAM, and use several assays to demonstrate the antibody’s potential as an oncology tool. In one series of assays the biotinylated antibody was combined with streptavidin-ZAP (Cat. #IT-27), and in conjunction with photochemical internalization was shown to have specific cytotoxicity on several different cancer cell lines over a range of concentrations.

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

Leoni G, Rattray M, Fulton D, Rivera A, Butt AM (2014) Immunoablation of cells expressing the NG2 chondroitin sulphate proteoglycan. J Anat 224(2):216-227. doi: 10.1111/joa.12141

Summary: In this work the authors use an antibody against the NG2-glia marker chondroitin sulphate proteoglycan (CSPG) along with Mab-ZAP (Cat. #IT-04) on cell lines and brain slices to eliminate cells expressing CSPG. The results demonstrate selective and effective killing, providing a method to study the function of these cells.

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

Hess SM, Young EF, Miller KR, Vincent BG, Buntzman AS, Collins EJ, Frelinger JA, Hess PR (2013) Deletion of naive T cells recognizing the minor histocompatibility antigen HY with toxin-coupled peptide-MHC class I tetramers inhibits cognate CTL responses and alters immunodominance. Transpl Immunol 29(1-4):138-145. doi: 10.1016/j.trim.2013.10.005

Summary: The authors utilized biotinylated peptide-MHC class I tetramers with Streptavidin-ZAP (Cat. #IT-27) to selectively delete a specific population of alloreactive T cells in mice. Animals received iv 33-pmol injections of the toxic tetramer, and the data indicate that these toxic tetramers can prevent the induction of donor-specific responses that result in organ rejection.

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

Q: Some suppliers sell their streptavidin conjugates in amounts given as streptavidin equivalents. Is that also the case for your product, Streptavidin-ZAP? What is important to me is to know what the molar concentration of streptavidin conjugate is, and the volume of your preparation.

A: The molar concentration of Streptavidin-ZAP (Cat. #IT-27) will depend on the lot; the accompanying data sheet will contain the molecular weight. We recommend that you mix Streptavidin-ZAP and your biotinylated material at equimolar concentrations. For our in-house in vitro quality control assays, we make a stock vial containing both 1 mM of biotinylated material and 1 mM of Streptavidin-ZAP diluted in media in 150 ml total volume. From this stock vial, we add 10 ml to each well of a plate containing cells in 90 µl volumes, which then dilutes the stock material to its correct concentration of 100 nM.

Check out the calculators on our website:

• Calculate Volume Required to Dilute a Solution
• Calculate Molarity of a Solution
• Calculate Volume of a Solution
• Calculate Mass of a Solution
• Convert Between Moles and Grams
• Convert Molar Units
• Convert Liter Units

Q: So, each mole of streptavidin will bind 4 moles of biotin?

A: Streptavidin-ZAP was created for use as an initial diagnostic step with biotinylated targeting agents, before moving on to a direct linkage between the optimal targeting agent and Saporin. The biotin-streptavidin interaction should be considered a linker; the major players are the targeting agent and Saporin. The targeting agent to Saporin ratio is kept at 1:2 M. When pre-mixing the biotinylated moiety with Streptavidin-ZAP in an equimolar ratio the ability of Streptavidin-ZAP to bind up to 4 biotins ensures that most of the biotinylated moiety will have Streptavidin-ZAP attached (no free biotinylated moiety). Streptavidin equivalents would not be appropriate as the Saporin moiety in Streptavidin-ZAP is the primary focus of the technology.