Streptavidin-ZAP (streptavidinylated saporin) combines with your biotinylated material to make a targeted toxin.
Unlike a secondary antibody binding to a primary antibody, the bond between streptavidin and biotin is rapid, essentially non-reversible, unaffected by most extremes of pH, organic solvents and denaturing reagents. It is essentially the strongest known noncovalent biological bond between protein and ligand.
Streptavidin-ZAP is super modular and works with biotinylated antibodies, peptides, growth factor, aptamers, anything that will recognize a cell surface receptor and can be biotinylated.
We have kits available which will also include an appropriate control conjugate depending on the species of antibody you’re using or if you’re using a peptide.
There are dozens of publications of using Streptavidin-ZAP in vivo.
Lee H, Hor CC, Horwitz LR, Xiong A, Su XY, Soden DR, Yang S, Cai W, Zhang W, Li C, Radcliff C, Dinh A, Fung TLR, Rovcanin I, Pipe KP, Xu XZS, Duan B (2025) A dedicated skin-to-brain circuit for cool sensation in mice. Nat Commun 16(1):6731. doi: 10.1038/s41467-025-61562-y PMID: 40721582
Objective: To investigate the functional contributions of specific spinal dorsal horn neuron subtypes to cold and pain sensation using targeted ablation and optogenetic tools.
Summary: The study identifies Calb1+ spinal neurons as essential mediators of cool sensation in mice. Behavioral and physiological responses following targeted ablation reveal distinct sensory processing roles for various neuronal subtypes.
Usage: Bombesin-SAP (IT-40), or control conjugate Blank-SAP (IT-21), was administered intrathecally at a dose of 400 ng in 10 μL sterile saline to ablate GRPR+ spinal neurons and assess their role in sensory behavior.
When or Why should you switch from using a secondary conjugate (like Fab-ZAP or Streptavidin-ZAP) to a direct saporin conjugate?
If you are working in vitro and using our secondary conjugates to specifically screening numerous targeting agents, then I would say “stay the course” and continue using these types of products. They are quick, effective and economical in screening antibodies.
However, if you are working in vivo and have been using our Streptavidin-ZAP to screen your biotinylated targeting agent, I would strongly suggest you contact us about performing a direct saporin conjugation.
Two reasons why you would want a direct conjugate:
1st is Cost effectiveness. Streptavidin-ZAP is great at assessing your targeting agent, but when looking downstream at the cost to create bulk mg sized batches, a direct conjugate would provide double the yield with equivalent cost.
2nd is Homogeneity. Since the targeting agent is directly-labeled with saporin, we end up with a product that is more homogeneous versus a conjugate made with various components and various labeling.
pHast Conjugates are one of our fastest tools to quantitatively test your primary antibody’s specificity, binding, and internalization, providing results in 1 day.
The pHast conjugate binds to your primary antibody via a secondary antibody cross-linked to a pH-dependent fluorescent reporter. This fluorescent reporter will increase intensity as the pH of its surroundings becomes more acidic, such as you would see on the inside of a cell.
pHast conjugates can be used with any fluorescence visualization device like a fluorescent plate reader, fluorescent microscope and can be used to illuminate your lead antibody candidates with same-day results.
Saporin conjugates can be used to create animal knockout models including Alzheimer’s Disease, Parkinson’s Disease, narcolepsy, epilepsy, and amyotrophic lateral sclerosis (ALS)
Genetic knockouts can be expensive, time-consuming, and with unwanted conditions
Disease models with saporin conjugates are ready in 2 weeks and are less expensive
Nazmuddin M, Stammes MA, Klink PC, Vernes MK, Bakker J, Langermans JAM, van Laar T, Philippens IHCHM (2025) Stereotactic lesioning of cholinergic cells by injection of ME20.4 Saporin in the nucleus basalis of Meynert in a rhesus monkey (Macaca mulatta). J Neuropathol Exp Neurol nlaf081. doi: 10.1093/jnen/nlaf081 PMID: 40673943
Objective: To describe a procedure to inject ME20.4-SAP, an immunotoxin that specifically binds to and depletes cholinergic neurons stereotactically into the nucleus basalis of Meynert (NBM) of a rhesus monkey (Macaca mulatta).
Summary: A digital non-human primate brain atlas was co-registered to the brain of the monkey. A custom-designed cranial chamber was also implanted to the skull to guide the injection. The effects of the ME20.4-SAP injections were evaluated in vivo with PET-CT using [18F]-FEOBV as a radiotracer. This approach yielded reliable spatial accuracy and successful delivery of ME20.4-SAP into the NBM. This saporin-mediated selective destruction of cholinergic neurons in the NBM, using MRI-guidance and a cranial chamber, offers a promising method to study the pathophysiology of NBM degeneration and possible therapeutic interventions.
Usage: The first dose was chosen based on previous NBM lesioning works in common marmosets where infusing 1.4 μg ME20.4-SAP (Cat. #IT-15, in a concentration of 0.20 μg/μl) into each side of the NBM produced partial NBM depletion. At the second injection session, 5 μg ME20.4-SAP (in 0.5 μg/μl solution) was administered into each NBM side.
Ren X, Wang Y, Zhang Y (2025) Targeted depletion of dysfunctional hematopoietic stem cells mitigates myeloid-biased differentiation in aged mice. Cell Discov 11:56. doi: 10.1038/s41421-025-00810-3 PMID: 40490480
Objective: To develop and evaluate a targeted strategy for depleting dysfunctional, myeloid-biased CD150-high hematopoietic stem cells (HSCs) in aged mice to restore balanced hematopoiesis and mitigate aging-related blood disorders.
Summary: The study used an antibody-toxin conjugate to selectively eliminate CD150-high HSCs, improving lymphoid-to-myeloid ratios, reducing platelet hyperproduction, and restoring hematopoietic balance in aged mice. Treatment preserved functional CD150-low HSCs and showed minimal off-target or systemic toxicity.
Usage: Streptavidin-ZAP (IT-27) was combined with a biotinylated anti-CD150 antibody to generate Anti-CD150-SAP (IT-103). This conjugate was used at doses of 1–2 mg/kg in vivo and as low as 0.01 nM in vitro to specifically deplete CD150-high HSCs while sparing CD150-low populations.
Roberts AG, Meyer L, Norton M, Phuah P, Alonso AM, Dowsett GKC, Cheng S, Dunsterville C, Liu J, Chung PE, Tao Y, Smitherman-Cairns T, Deutsch AB, Chatterjee A, Lam BYH, Hanyaloglu AC, JOnes B, Yeo GSH, Salem V, Murphy KG (2025) Enteropancreatic neurons drive the glucoregulatory response to ingested lipid. bioRxiv 2025.05.09.652620. doi: 10.1101/2025.05.09.652620
Objective: To determine whether NTSR1-expressing enteropancreatic neurons mediate the glucose-lowering effects of dietary olive oil and neurotensin, and to characterize their physiological role in glucose homeostasis.
Summary: The study demonstrates that neurotensin improves glucose tolerance by activating NTSR1-expressing enteropancreatic neurons, which connect the gut and pancreas. Ablation or disruption of these neurons abolished the glucoregulatory effects of both neurotensin and olive oil, establishing their necessity and sufficiency in this pathway.
Usage: Neurotensin-SAP (IT-56) or Blank-SAP (IT-21) was unilaterally injected into the nodose ganglia (0.5 μL at 1.5 μg/μL) to ablate NTSR1-expressing vagal neurons. This targeted lesioning helped confirm that peripheral vagal neurons were not responsible for mediating the glucose-lowering effects of neurotensin.
