Park HB, Kim KH, Kim JH, Kim SI, Oh YM, Kang M, Lee S, Hwang S, Lee H, Lee T, Park S, Lee JE, Jeong GR, Lee DH, Youn H, Choi EY, Son WC, Chung SJ, Chung J, Choi K (2024) Improved safety of chimeric antigen receptor T cells indirectly targeting antigens via switchable adapters. Nat Commun 15(1):9917. doi: 10.1038/s41467-024-53996-7 PMID: 39557825

Objective: To show that switchable CAR-T cells with a tumor targeting adaptor can mitigate on-target off-tumor toxicity against a low selectivity tumor antigen that cannot be targeted by conventional CAR-T cells, such as CD40.

Summary: The system is composed of anti-cotinine murine CAR-T cells and cotinine-labeled anti-CD40 single chain variable fragments (scFv), with which the authors show selective tumor killing while sparing CD40-expressing normal cells including macrophages in a mouse model of lymphoma. The authors evaluated whether Cot CAR-T cells could be depleted by Cot-saporin in vivo in an allogeneic CAR-T cell transfer model. When Balb/C mice transplanted with B6 bone marrow cells were injected with B6 Cot CAR-T cells, the transferred Cot CAR-T cells expanded in the peripheral blood in response to Balb/C alloantigen. However, when Cot-saporin was administered during this expansion phase, the Cot CAR-T cells failed to expand and were subsequently eliminated in the blood. Thus, Cot-saporin-mediated CotCAR-T cell suicide was confirmed in vitro and in vivo.

Usage: in vitro Cot CAR-T cell depletion by cotinine-drug conjugates: Peptides were incubated with saporin-labeled streptavidin (IT-27) at a molar ratio of 4:1 to generate cotinine-saporin conjugate (Cot-saporin). For Cot-saporin-dependent cytotoxicity assays on Cot CAR-T cells, a 1:1 mixed population (50,000 cells each) of Cot CAR-T cells (target cells) and control T cells (bystander non-CAR-T cells) were incubated with various doses of Cot-saporin for 48 h in medium containing human IL-2. Seven days after CAR-T cell transfer, Cot-saporin was administered intraperitoneally three times at 3-day intervals.

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

Bryder D, Konturk-Ciesla A, Zhang Q, Kharazi S (2024) A non-invasive stem cell therapy boosts lymphopoiesis and averts age-related blood diseases in mice. Research Square doi: 10.21203/rs.3.rs-4528815/v1

Objective: To develop a murine transplantation model based on low-intensity conditioning protocols using antibody-mediated Hematopoietic stem cell.

Summary: Authors demonstrate that young HSCs, once transplanted, survive and thrive in aged hosts, dramatically improving hematopoietic output and ameliorating age-compromised lymphopoiesis.

Usage: Intravenous injection of CD45-SAP (3 mg/kg, IT-91). Biotinylated anti-CD45.2 antibodies were mixed with streptavidin-saporin conjugate at a 1:1 molar ratio (IT-27).

Related Products: Anti-CD45.2-SAP (Cat. #IT-91), Streptavidin-ZAP (Cat. #IT-27)

Simpson J, Starke CE, Ortiz AM, Ransier A, Darko S, Llewellyn-Lacey S, Fennessey CM, Keele BF, Douek DC, Price DA, Brenchley JM (2024) Immunotoxin-mediated depletion of Gag-specific CD8+ T cells undermines natural control of Simian immunodeficiency virus. JCI Insight e174168. doi: 10.1172/jci.insight.174168 PMID: 38885329

Objective: To investigate the role of gag epitope-specific CD8+ T cells in the immune control of Simian Immunodeficiency Virus (SIV) in a nonhuman primate model.

Summary: Antibody-mediated depletion studies suggest that CD8+ T cells suppress SIV replication, but bulk depletion of CD8+ T cells may increase SIV target cells. Authors selectively depleted CD8+ T cells specific to the CM9 epitope, but this didn’t suppress viral replication in SIV-infected rhesus macaques. The data indicate that CM9-specific CD8+ T cells alone are not sufficient for immune control of SIV.

Usage: Streptavidin-ZAP was added stepwise to purified CM9 monomers to a final molar ratio of 1:4 and administered intravenously at a doses of 350 pmol/kg, 500 pmol/kg, 1 nmol/kg, or 2 nmol/kg at various time intervals.

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

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.
• Leitman EM et al. Saporin-conjugated tetramers identify efficacious anti-HIV CD8+ T-cell specificities. PLoS One. 2017;12(10):e0184496.

Boucher A (2024) Unveiling cholera toxin binding and intoxication using enteroids and site-specific mutants. Univ Gothenburg Thesis.

Objective: To investigate the binding site requirements of cholera toxin in the human body.

Summary: The cause of cholera symptoms is cholera toxin secreted by bacteria once in the small intestine. Cholera toxin has multiple binding sites that lead to many different intake mechanisms. By identifying the binding sites responsible, the study seeks to lay the groundwork for better means of treatment.

Usage: Leukocytes were treated with biotinylated Cholera toxin B binding-deficient mutants mixed with Streptavidin-SAP (IT-27) and assessed for cell death.

Related Products: CTB-SAP (Cat. #IT-14), Streptavidin-ZAP (Cat. #IT-27), Recombinant Cholera Toxin B (Cat. #PR-14)

Matsuda T, Morigaki R, Hayasawa H, Koyama H, Oda T, Miyake K, Takagi Y (2024) Striatal parvalbumin interneurons are activated in a mouse model of cerebellar dystonia. Dis Model Mech 17(5):dmm050338. doi: 10.1242/dmm.050338 PMID: 38616770

Objective: To examine the influence of cerebellar abnormalities on the basal ganglia circuitry to investigate dystonia pathophysiology.

Summary: Dystonia is a disorder characterized by twisting, repetitive movements, and abnormal postures induced by sustained muscle contractions. This study utilized a cerebellar dystonia mouse model to examine the cerebellum’s contribution. The authors found that modulating parvalbumin (PV) interneurons might provide a novel treatment strategy.

Usage: In order to selectively ablate dorsolateral striatal PV interneurons, Streptavidin-ZAP (Cat. #IT-27) was mixed equimolar with biotinylated anti-PV and diluted with PBS by 1:100 and 3 ul injected into the striatum of mice. BIgG-SAP Rabbit (Cat. #IT-75) was used as the control.

Related Products: Streptavidin-ZAP (Cat. #IT-27), BIgG-SAP Rabbit (Cat. #IT-75)

Komatsu N, Kosai A, Kuroda M, Hamakubo T, Abe T (2024) Cetuximab-toxin conjugate and npe6 with light enhanced cytotoxic effects in head and neck squamous cell carcinoma in vitro. Biomedicines 12(5):973. doi: 10.3390/biomedicines12050973 PMID: 38790935

Objective: Combine the use of antibody-directed saporin and a photosensitizer to exert directed and improved cytotoxicity towards carcinoma cells as compared to either by itself.

Summary: Photodynamic therapy uses photosensitizers and irradiation to exert cytotoxic effects on cancer. When combined with biotinylated anti-EGFR conjugated to Strep-ZAP (IT-27), an increased cytotoxicity was hypothesized. The method developed enhanced the cytotoxicity of anti-EGFR-Strep-ZAP by the photodynamic effect in Sa3 and HO-1-u-1 cells, which have moderate levels of EGFR expression.

Usage: Cells were seeded on a 96-well plate and delivered 1.34 pM to 4.2 nM of anti-EGFR or anti-EGFR-Strep-ZAP, and cell viability was measured with formazan.

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

Yelamali AR, Chendamarai E, Ritchey JK, Rettig MP, DiPersio JF, Persaud SP (2024) Streptavidin-drug conjugates streamline optimization of antibody-based conditioning for hematopoietic stem cell transplantation. bioRxiv 2024.02.12.579199. doi: 10.1101/2024.02.12.579199 PMID: 38405731

Objective: Use biotinylated CD45.2 antibodies conjugated to Streptavidin to target hematopoietic stem cells (HSCs) for HSC transplantation.

Summary: Hematopoietic stem cell transplantation offers a promising alternative to standard cancer treatments. Using Click Chemistry, different toxic payloads were attached to streptavidin and observed.

Usage: 75 micrograms of CD45.2 delivered to HSCs deriving from B6 mice.

Related Products: Anti-CD45.2-SAP (Cat. #IT-91), Streptavidin-ZAP (Cat. #IT-27)

Zhao Q, Zong H, Zhu P, Su C, Tang W, Chen Z, Jin S (2024) Crosstalk between colorectal CSCs and immune cells in tumorigenesis, and strategies for targeting colorectal CSCs. Exp Hematol Oncol 13(1):6. doi: 10.1186/s40164-024-00474-x PMID: 38254219

Summary: Cancer immunotherapy has become a promising strategy in the treatment of colorectal cancer, and relapse after tumor immunotherapy. Cancer stem cells (CSCs) have the capabilities of self-renewal and differentiation and are also resistant to the traditional therapies of radiotherapy and chemotherapy. The authors review strategies for targeting colorectal CSCs, where one method described uses a biotinylated antibody against EpCAM (clone 3-171) conjugated to saporin via Streptavidin-ZAP (IT-27).

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

See Also:

• Lund K et al. 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, 2014.

Allred CA, Gormley C, Venugopal I, Li S, McGuire MJ, Brown KC (2023) Tumor-specific intracellular delivery: peptide-guided transport of a catalytic toxin. Commun Biol 6(1):60. doi: 10.1038/s42003-022-04385-7 PMID: 36650239

Objective: The demonstration of a peptide optimized by chemical modifications for tumor specificity to deliver saporin, a catalytic toxin, specifically to cancer cells via both in vitro and in vivo.

Summary: Peptides rival antibodies in affinity and specificity and offer an alternative as cancer-targeting molecules. In comparison to antibodies, peptides have a faster development time and lower production cost. The authors isolated peptide MGS4, derived from a phage-displayed library using a non-small cell lung cancer (NSCLC) cell line as the target. MGS4 was modified to identify the minimal binding domain while also improving affinity and stability. Importantly, the authors provide data showing the peptide delivered saporin both in vitro and in vivo to cancer cells demonstrating anti-tumor efficacy in a mouse model.

Usage: In vitro delivery was performed by reacting biotinylated peptide with Streptavidin-ZAP (Cat. #IT-27) in a 1:1 molar ratio. Cells were treated for 6h at 37C. The drug was removed and replaced with media and after 72 hours, cell viability was measured with CellTiter-GLO. In vivo delivery was performed using biotinylated MGS4 reacted with Streptavidin-ZAP and administered via tail-veil injection (7.5 ug/100 ul) 2x/week for 2.5 weeks for a total of 5 treatments.

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

Heck AJ (2023) Chemical design of a supramolecular protein nanoplatform for therapeutic applications. Univ Johannes Gutenberg Thesis.

Objective: Investigate the potential of using multivalent proteins as an integrative nanoplatform to target protein hallmarks in various diseases by forming supramolecular protein conjugates (SPC).

Summary: The author employs an integrative and adaptable protein-based nanoplatform to combine bioactive entities at the macromolecular level to design multivalent protein-conjugates for versatile therapeutic purposes. Multivalent protein-conjugates, a tetrameric protein with up to four ligand binding sites functions is used as a supramolecular “glue” utilizing avidin-biotin technology. The study investigates the assembly of diverse bioactive components into well organized multifunctional protein-conjugates, ultimately leading to the formation of supramolecular protein conjugates (SPC) that target protein signatures in a variety of diseases.

Usage: Streptavidin-ZAP with Anti-PSMA Antibody

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

See Also:

• Kuroda K et al. Saporin toxin-conjugated monoclonal antibody targeting prostate-specific membrane antigen has potent anticancer activity. Prostate 70(12):1286-1294, 2010.