We’re highlighting one of our antibodies, a rabbit polyclonal against Melanopsin. This antibody is offered as both serum (AB-N38) and affinity purified (AB-N39). Intrinsically photosensitive retinal ganglion cells (ipRGCs) are cells that express melanopsin. These ipRGCs, with their long processes, are involved in the perception of light and dark and are circadian rhythm determinants. Our Melanopsin antibody recognizes a portion of the N-terminal region of the mouse melanopsin extracellular domain and does not cross-react with melanopsins of other species, so it’s specific to mouse.
Here is how other researchers are using them in recent publications. This Melanopsin antibody may be the antibody your lab needs.
Kim et. al. used (AB-N38) at a 1:2,000 dilution to quantify ipRGCs in the retina and confirm that Per1-deficiency did not affect melanopsin-positive cell abundance.
And finally, Zhu et. al. using affinity purified (AB-N39) at a 1:2000 dilution to identify and quantify ipRGCs in retinal whole-mounts following ischemic injury.
How is a targeted toxin able to inhibit a cellular process when an antagonist did not?
An antagonist is used to block a receptor on a cell to keep it from binding a target molecule and activating the cell.
For example, a substance P antagonist binds to the substance P (NK-1) receptor. The hypothesis was that if the antagonist binds to the receptor, substance P can’t bind and the cell won’t be activated.
The reality is that there are other receptors besides the substance P receptor on that cell. If any of these other receptors bind to their target molecules, then the cell will still be activated.
The Targeted Toxins with our targeting technology can use any of these cell surface receptors to target and completely eliminate the entire cell. Since there are no receptors left to bind; no cell left to be activated.
Importantly, our conjugates cleanly remove one particular cell type and don’t damage bystander cells.
Once the debris from the targeted cell is cleared away, there is nothing remaining to interfere or affect the normal action/interaction of other cells.
Have you been wondering if ordering in bulk is the better move for your upcoming project? Wondering if there is pricing incentive when buying larger quantities? The quick answer is yes!
The best cost per microgram is larger 1 mg size, where we typically give the biggest price break and seeing upwards of a 20% discount when comparing four 250 ug vials and the 1 mg vial.
Another benefit of ordering in bulk is maintaining lot consistency for your project. This allows you to develop a consistent protocol and not have to be concerned with variability in batch-to-batch protein concentrations.
We understand that typically the upfront cost of buying in bulk can be the limiting factor, so I want to take a second and let you know that we also offer plans where you can reserve 1-2 mg over a 12-month period for a specific lot, and just pay for the amount that you draw down.
ATS offers a custom biotinylation service to biotinylate antibodies and peptides, especially when customers plan to use them with our Streptavidin-ZAP.
We have been seeing a trend of variability with commercially available antibodies, where customers will see over or under derivatization of material and this can be an issue if you plan to use it with Streptavidin-ZAP.
There are a few fundamentals to look for when choosing/creating your biotinylated targeting agent:
(1) the linker doesn’t impair target-binding affinity,
(2) the linker should be stable and
(3) the linker should be able to release payload efficiently.
Important details to know about your biotinylated targeting agent:
(1) the ratio of biotin to the protein,
(2) unreacted biotin is purified away
(3) the length of linker because long linkers could interfere with binding and
(4) location of where biotin is attached such that important protein side-chains weren’t impacted.
If any of these parameters are unfamiliar to you or you weren’t given these details, then I strongly encourage you to talk to us about a custom biotinylation service.
Pandala N, De Melo Haefeli L, Lang M, Stone EM, Mullins RF, Tucker BA, Han IC (2025) Development of a targeted choroidal injury model for the study of retinal degenerations and therapeutic cell replacement. bioRxiv 2025.07.29.667466. doi: 10.1101/2025.07.29.667466
Summary: The choroid is a vascular structure that provides nutrients to the photoreceptors by diffusion as well as removal of waste from the outer retina, essentially enabling proper retinal function. Loss of the choroid is a crucial pathophysiologic step in a wide range of retinal diseases. However a current limitation in developing choroidal cell replacement is the lack of a reliable injury model to allow study of transplantation strategies. Existing models rely on either ablative injury to the choroid with laser photocoagulation, but can damage unintended structures, or systemic sodium iodate administration, which causes diffuse, progressive choroidal injury. Authors were able to show suprachoroidal injection of anti-CD38 and anti-CD105 saporin conjugates resulted in targeted, localized, and non-progressive choroidal injury in rats. Immunotoxin-based models of targeted choroidal injury may be useful for understanding pathways of retinal degeneration and facilitating development of therapies for diseases involving choroidal cell loss.
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
