The development of the antibody drug conjugate (ADC) has revolutionized the field of biotherapeutics, representing a significant stride in next-gen biologic leads discovery. These complex molecules combine the precision of a monoclonal antibody with the potency of a cytotoxic payload. However, the success of an ADC drug relies on more than just binding affinity. The antibody must successfully transport the toxic payload into the target cell. This process is known as internalization. Without effective internalization, the payload remains outside the cell and cannot exert its therapeutic effect.
Therefore, identifying antibodies that not only bind to a target but also trigger rapid uptake is a critical step in development. Creative Biolabs' internalizing antibody screening service utilizes advanced phage display for ADC development. We provide a robust platform to identify high-affinity antibodies with superior internalization properties, accelerating the path from target selection to lead candidate identification.
An ADC functions by delivering a cytotoxic agent directly to a specific cell type. The mechanism of action follows a strict biological pathway.
Fig.1 Mechanism of action for ADC internalization and drug release.1,3
If the antibody stays on the cell surface, the drug is never released. Consequently, standard binding assays are insufficient for ADC internalizing antibody discovery. Researchers must screen specifically for monoclonal antibody internalization to ensure payload delivery occurs efficiently.
Phage display technology offers distinct advantages over traditional hybridoma methods for finding internalizing antibodies.
| Name | Format | Animal model | Target | Tissue/organ |
|---|---|---|---|---|
| E3A1 | scFv | CBA mice | Unknown | Thymus |
| K3.1 | scFv | Bourgogne brown rabbits | Carbonic anhydrase II | Atherosclerosis |
| P3 | scFv | Rabbit | Galectin-3 | Atherosclerosis |
| SCA A1 and SCA B1 | scFv | Rats | Unknown | Pancreatic islets |
| 269 | scFv | Cancer patients | Unknown | Tumor-targeting ligands |
| C-C7 | Llama VHH | Mice | Dynactin-1-p150Glued | Glioma |
| scFv 4 and scFv 40 | scFv | Rat | Unknown | BBB |
| RG3 | sdAb | CD1 mice | Unknown | BBB |
| C5 | sdAb | Mice | Unknown | cNHL |
We employ proven strategies to isolate antibodies that enter cells efficiently. We customize these methods based on your specific target and research goals.
This is the most direct method for rapid internalization antibody screening. It selects for phage that are physically taken up by the cell. We incubate the phage library with living cells at 37°C to allow endocytosis. After rigorous washing to remove surface binders, we lyse the cells to recover only the internalized particles. This method effectively filters out binders that stay on the surface.
For targets where the natural ligand is known to internalize, we design competitive screens. We look for antibodies that mimic the action of the natural ligand or trigger the same uptake pathway. This ensures that the antibody utilizes an established route for entry, leading to reliable payload delivery.
An ideal ADC antibody binds tightly at neutral extracellular pH (7.4) but releases its cargo at acidic endosomal pH (5.0-6.0). Our platform screens for this specific trait by selecting phage that bind at neutral pH but dissociate at acidic pH. This facilitates efficient recycling of the receptor and ensures the payload remains trapped inside the cell for maximum potency.
We follow a structured workflow to ensure high-quality results.
Choose from immune, naive, or synthetic libraries (scFv, Fab, VHH).
Outcome: A diverse pool of starting candidates.
Remove phage that bind to non-target cells.
Outcome: Reduced background noise and false positives.
Perform cell-based internalization selection or pH-specific panning.
Outcome: Enrichment of internalizing clones.
Analyze individual clones using high-throughput flow cytometry (FACS) or microscopy.
Outcome: Confirmation of monoclonal antibody internalization.
Sequence DNA and characterize kinetics.
Outcome: Validated sequences ready for production.
Finding a candidate is only the first step. We validate the hits to prove they work.
We use flow cytometry to track the location of the antibody. By using fluorescent labels that are quenched (dimmed) on the outside of the cell but remain bright inside, we can quantify exactly how much antibody has been internalized. This provides a clear metric for rapid internalization antibody screening.
Visual confirmation is powerful. We provide high-resolution images showing the localization of your antibody within the cell. You will see colocalization with endosomal or lysosomal markers. This confirms that the antibody has reached the correct compartment for ADC payload delivery antibody function.
We measure the rate of internalization. Some antibodies enter cells in minutes, while others take hours. Knowing the kinetics helps you predict the efficacy of the ADC drug in later stages.
Choosing the right partner for ADC internalizing antibody discovery is vital for your project timeline.
While ADCs are primarily associated with cancer therapy, internalizing antibodies have broader applications.
Our internalizing antibody screening service is applicable to any research project requiring specific intracellular delivery.
The success of an antibody-drug conjugate hinges on the ability of the antibody to enter the cell. Without this crucial step, even the most potent payload is ineffective. Our specialized service for ADC internalizing antibody discovery removes the guesswork. We provide you with candidates that are functionally validated to internalize, giving your ADC drug development program the best possible start. Leverage our expertise in phage display for ADC development to unlock new therapeutic possibilities.
Q: What is the timeline for a typical project?
Q: Why should I choose phage display over traditional hybridoma technology for ADC internalizing antibody development?
A: Phage display offers a massive throughput advantage, allowing us to screen billions of antibody variants simultaneously to find rare high-affinity candidates. Unlike hybridoma, we can precisely manipulate selection conditions, such as adjusting temperature or using competitive elution, to specifically enrich for antibodies that trigger rapid receptor-mediated endocytosis. This targeted approach significantly shortens your ADC discovery timeline and increases the probability of identifying functional leads.
Q: ADC drugs need to release toxins in the lysosome; can you screen for antibodies with pH-dependent binding properties?
A: Yes, this is a core feature of our service. We implement specific pH-dependent screening protocols to select antibodies that bind tightly at neutral pH (extracellular environment) but dissociate rapidly at acidic pH (endosomal/lysosomal environment). This binding-release mechanism is crucial for facilitating receptor recycling and ensuring that the toxic payload is efficiently released within the specific intracellular compartment, thereby significantly enhancing the therapeutic index of your ADC.
Q: How does your screening strategy specifically distinguish between antibodies that just bind to the cell surface and those that actually internalize?
A: We employ a rigorous live-cell internalization panning strategy to solve this. After incubating the phage library with your target cells at 37°C to allow endocytosis, we perform a strict surface stripping or acid wash step. This effectively removes any phage bound to the surface but not internalized. We then lyse the cells to recover only the phage that successfully entered the cell, ensuring that the final candidates possess confirmed internalizing capabilities.
Q: Is this service suitable for clinical diagnostics?
A: No. This service is strictly for research purposes and early-stage drug discovery. The antibodies produced are not approved for use in clinical diagnosis or treatment in humans.
Please kindly note that our services can only be used to support research purposes (Not for clinical use).
Creative Biolabs is a globally recognized phage company. Creative Biolabs is committed to providing researchers with the most reliable service and the most competitive price.
