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.
Dib C, Queenan J, Willner H, Swartzrock L, Charlesworth C, Denis M, Davis J, Nakauchi H, Liu DR (2025) Combining hsc base-editing with anti-cd117 antibody conditioning to correct severe combined immunodeficiency disorder in a novel mouse model. Transplantation and Cellular Therapy 31(2):S253-S354. doi: 10.1016/j.jtct.2025.01.385
Objective: To test whether base-edited hematopoietic stem cells (HSPCs) combined with non-genotoxic antibody conditioning can correct severe combined immunodeficiency (SCID) in a novel Rag2 mutant mouse model.
Summary: Base-editing delivered via engineered virus-like particles successfully corrected Rag2 mutations in HSPCs, which restored lymphocyte development following transplantation. Conditioning with an Anti-CD117-Saporin conjugate enabled efficient engraftment without irradiation toxicity, demonstrating a safer strategy for SCID treatment.
Usage: Mice were conditioned with Anti-CD117-SAP (IT-83) at 1.5 mg/kg intravenously prior to transplantation of base-edited or wild-type HSPCs.
Goodman RL, Moore AM, Onslow K, Hileman SM, Hardy SL, Bowdridge EC, Walters BA, Agus S, Griesgraber MJ, Aerts EG, Lehman MN, Coolen LM (2023) Lesions of kndy and kiss1r neurons in the arcuate nucleus produce different effects on lh pulse patterns in female sheep. Endocrinology 164(11):bqad148. doi: 10.1210/endocr/bqad148 PMID: 37776515
Objective: To test the functional role of ovine KNDy neurons in pulse generation and identify the roles of nearby Kiss1 receptor (Kiss1R)-containing cells.
Summary: Injection of NK3-SAP (NKB-SAP) ablated over 90% of the KNDy cells, Kiss-SAP lesioned about two-thirds of the Kiss1R population. This led to a significant decrease in LH pulse amplitude and altering LH pulse patterns. NK3-SAP increased the interpulse interval without affecting the regularity of LH pulses, whereas Kiss-SAP disrupted their regular hourly occurrence but not the interpulse interval. The findings suggest that KNDy neurons are critical for GnRH pulse generation in ewes, while ARC Kiss1R cells support the amplitude and regularity of these pulses, possibly as part of a positive feedback loop involving GABA or glutamate.
Usage: Saporin conjugates were injected into the arcuate nucleus. Kiss-SAP (kisspeptin54-SAP) was diluted to 700 ng/μL in PBS immediately before use. In preliminary work to test the effectiveness of Kiss-SAP, a single unilateral injection (1 μL of 700 ng/μL) of this conjugate was made in the preoptic area of 3 ewes. The contralateral side was used as control and either received no injections or Blank-SAP (1 μL of 700 ng/μL) (IT-21).
