zap-conjugates

Yuan X, Yang M, Chen X, Zhang X, Sukhadia S, Musolino N, Bao H, Chen T, Xu C, Wang Q, Santoro S, Ricklin D, Hu J, Lin R, Yang W, Li Z, Qin W, Zhao A (2017) Characterization of the first fully macropinocytosing human antibodies human anti-TEM1 scFv in models of solid tumor imaging and immunotoxin-based therapy. Cancer Immunol Immunother 66:367-378.. doi: 10.1007/s00262-016-1937-z

Summary: Tumor endothelial marker 1 (TEM1) has been identified as a novel surface marker upregulated on the blood vessels and stroma in many solid tumors. The authors previous isolated a single-chain variable fragment (scFv) 78 against TEM1 from a yeast display scFv library and evaluated potential applications of scFv78 as a tool for tumor molecular imaging, immunotoxin-based therapy and nanotherapy. MS1 and MS1-hTEM1 cells were treated with site-specifically biotinylated scFv78 conjugated with the Streptavidin-ZAP (Cat. #IT-27) at a molar ratio of 4:1 (scFv78:ZAP) starting from 40 nM serially diluted down to 0.04 nM. The scFv78-saporin immunoconjugate exerted dose-dependent cytotoxicity with high specificity to TEM1-positive cell in vitro. The data indicate that scFv78, the first fully human anti-TEM1 recombinant antibody, recognizes both human and mouse TEM1 and has features advantageous for the development of imaging probes or antibody-toxin conjugates for a large spectrum of human TEM1-positive solid tumors.

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

Pires E, D’Souza R, Needham M, Herr A, Jazaeri A, Li H, Stoler M, Anderson-Knapp K, Thomas T, Mandal A, Gougeon A, Flickinger C, Bruns D, Pollok B, Herr J (2015) Membrane associated cancer-oocyte neoantigen SAS1B/ovastacin is a candidate immunotherapeutic target for uterine tumors. Oncotarget 6:30194-30211. doi: 10.18632/oncotarget.4734

Summary: Ovastatin is a zinc matrix metallo-proteinase thought to play roles in sperm-egg interaction and the prevention of polyspermy in eutherians. This protein is not found in normal adult tissues, but is expressed by uterine carcinosarcomas. The authors investigated the possibility of targeting ovastatin as a tumor surface neoantigen for therapeutic purposes. SNU539 cells, a uterine malignant mixed Müllerian tumor-derived cell line, were challenged with 1 μM, 0.1 μM, and 0.01 μM rabbit polyclonal anti-ovastatin coupled to 5.42 nM Fab-ZAP rabbit (Cat. #IT-57). Rabbit IgG-SAP (Cat. #IT-35) was used as a control. The results indicate that for this form of uterine cancer, ovastatin is a viable therapeutic target.

Related Products: Fab-ZAP rabbit (Cat. #IT-57), Rabbit IgG-SAP (Cat. #IT-35)

Damelin M, Bankovich A, Park A, Aguilar J, Anderson W, Santaguida M, Aujay M, Fong S, Khandke K, Pulito V, Ernstoff E, Escarpe P, Bernstein J, Pysz M, Zhong W, Upeslacis E, Lucas J, Lucas J, Nichols T, Loving K, Foord O, Hampl J, Stull R, Barletta F, Falahatpisheh H, Sapra P, Gerber H, Dylla S (2015) Anti-EFNA4 calicheamicin conjugates effectively target triple-negative breast and ovarian tumor-initiating cells to result in sustained tumor regressions. Clin Cancer Res 21:4165-4173. doi: 10.1158/1078-0432.CCR-15-0695

Summary: Triple-negative breast cancer (TNBC) is characterized by tumors lacking HER2, estrogen receptor, and progesterone receptor. TNBC has proved to be very difficult to treat, in large part because of the absence of consensus targets on the surface of the tumor cells. In this work the authors empirically established a set of surface markers associated with TNBC tumor initiating cells, as produced by patient-derived xenografts. Ephrin-A4 was selected as a therapeutic target, and a cell line transfected with the ephrin-A4 gene was challenged with two versions of biotinylated anti-ephrin-A4 coupled to Streptavidin-ZAP (Cat. #IT-27). Both the mouse monoclonal and the humanized antibodies reach an EC50 of 10 ng/ml, indicating that ephrin-A4 has promise as a therapeutic target for TNBC.

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

Q: For in vitro cytotoxicity assays, could you tell me: 1) whether you incubate primary with your Saporin secondary for a specific amount of time prior to cell addition, and 2) do you use a single concentration of secondary per well or a primary:secondary ratio — like 1:2 or 1:4?

A: The primary antibody should be incubated with the ZAP product for 20 min prior to addition to the cells. Internalization often happens so quickly that you would lose some efficacy due to the antibody being bound and internalized prior to the ZAP product complexing with the primary. We do recommend maintaining a constant 5 nM (~ 45 ng/well) concentration of the ZAP product in the well and titrating your primary only. This way the EC50 you generate will be the EC50 of the primary antibody with all else held constant. The best starting concentration for your primary antibody is 10-100 nM in the well.

Related Products: ZAP Conjugates

Chua J, Vankemmelbeke M, McIntosh R, Clarke P, Moss R, Parsons T, Spendlove I, Zaitoun A, Madhusudan S, Durrant L (2015) Monoclonal antibodies targeting LecLex-related glycans with potent antitumor activity. Clin Cancer Res 21:2963-2974. doi: 10.1158/1078-0432.CCR-14-3030

Summary: In this work the authors characterized two monoclonal antibodies that target glycans containing Lewis carbohydrate antigens. One of the methods used was to combine varying concentrations of the antibodies with 50 ng mouse Fab-ZAP (Cat. #IT-48) and apply the conjugates to cells for 72 hours. The antibodies were demonstrated to have efficient internalization, supported by potent in vivo anti-tumor activity.

Related Products: Fab-ZAP mouse (Cat. #IT-48)

Higgins S, Fillmore H, Ashkan K, Butt A, Pilkington G (2015) Dual targeting NG2 and GD3A using Mab-Zap immunotoxin results in reduced glioma cell viability in vitro. Anticancer Res 35:77-84.

Summary: Human glioma-derived cell lines were sequentially incubated with anti-NG2 and anti-GD3A coupled to Mab-ZAP (Cat. #IT-04) at 1 μg/ml and 5 μg/ml for 72 hours each. The combination therapy was significantly more effective than single therapy in eliminating the glioma cells.

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

Ehrlich D, Wang B, Lu W, Dowling P, Yuan R (2014) Intratumoral anti-HuD immunotoxin therapy for small cell lung cancer and neuroblastoma. J Hematol Oncol 7:91. doi: 10.1186/s13045-014-0091-3

Summary: HuD protein is a 40-kDa neuronal RNA-binding protein that is expressed in 100% of small cell lung cancer (SCLC) tumor cells. An anti-HuD monoclonal was biotinylated and combined with Streptavidin-ZAP (Cat. #IT-27); this conjugate was tested both in vitro and in vivo. Anti-HuD-SAP eliminated NCI-H69 and Neuro-2a cells at an EC50 of <0.5 μg/ml. 1 mg/kg of the conjugate injected directly into subcutaneous tumors generated in mice resulted in a temporary lack of tumor growth or regression of the tumor. The results demonstrate the potential of HuD as a therapeutic target for SCLC and neuroblastoma.

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

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)