ADC and ODC Related Questions
CellMosaic provides antibody drug conjugate (ADC) and other drug conjugate (ODC) related products and services. Below are answers to frequently asked questions regarding the general applications and usage of these products. For specific product questions, please click here. For service-related questions, please click here.
How many antibodies can I label with CellMosaic’s ADC kit?
CellMosaic’s ADC kit is configured by the number of labeling reactions, not the number of antibodies. In the “Number of Reactions” section on each kit's product page on the website, selecting 1 will provide the price and catalog number for a one-reaction kit (x1). Choosing 3 gives you the price and catalog number for a three-reaction kit (x3), which is typically about 20% cheaper than purchasing three one-reaction kits.
What is the difference between ordering one three-reaction kit (x3) or three one-reaction kit (x1)?
Three one-reaction kits are ideal if you want to conduct three labeling reactions at different time points. A three-reaction kit, which is around 20% cheaper, is suited for performing three reactions simultaneously or within a short timeframe, as the buffers are packaged in a single tube for all reactions.
I have only a small amount of antibody; can I split the reagents for multiple labeling?
Unfortunately, no. The ADC kit includes only one or three sets of purification and buffer reagents. Splitting the reagents would prevent you from completing the conjugation and purification processes effectively.
Does CellMosaic sell protein-drug conjugation kits for single-domain antibodies (~15KDa)?
Yes, we currently offer four PerKit™ products that can be modified for 10-20 KDa antibodies: Protein Mertansine (DM1) Conjugation Kit (CM11414), Protein MMAE Conjugation Kit (CM11413), Protein Deruxtecan Conjugation Kit (CM11432), and Protein SN38 Conjugation Kit (CM11430). If your desired kit isn't listed, please contact us for potential customization.
How should I dispose of hazardous waste from my ADC or PDC conjugation kit?
To safely dispose of hazardous waste from our kits, place used columns and empty reagent tubes into the provided plastic waste bag, seal it, and dispose of the entire bag as solid lab waste according to local regulations. We recommend consulting your EHS specialists for specific hazardous waste disposal procedures.
Can I substitute PBS for the buffers included in my ADC conjugation kit if I'm concerned about antibody solubility?
No, substituting PBS for the kit buffers is not recommended. The buffer systems provided in our kits are essential for successful conjugation and have been extensively tested to ensure solubility and stability. However, if your antibody has unique properties and solubility concerns, please contact us for further guidance.
What can I do to reduce ADC aggregation?
Aggregation is typically caused by the hydrophobicity and stacking of the loaded drugs. CellMosaic’s ADC kits use clinically approved conventional linkers, such as VC-PAB, ethylene type for proof-of-concept studies, which can also add hydrophobicity and contribute to aggregation. To reduce aggregation, consider use a more water-soluble drug or a less hydrophobic linker, such as our super hydrophilic AqueaTether®(AqT®) linker. If altering your ADC configuration is not an option, reducing the drug-to-antibody ratio may help. For long-term storage, we recommend our ADC Stabilizing Buffer to minimize aggregation.
Which kit should I use to conjugate a ~50 KDa protein?
Any of our protein-drug conjugation kits can be used for a ~50 KDa protein. We currently offer kits for DM1, SN38, MMAE, Deruxtecan, and other small molecules with a carboxylic acid group. If the drug you're looking for isn’t listed, please inquire about custom conjugation services.
Note: Smaller proteins/antibodies may be more prone to aggregation with higher drug loading. For more details, see “What can I do to reduce ADC aggregation?
Can CellMosaic’s antibody-drug conjugation kits be used for nanobodies instead of antibodies?
No, our antibody-drug conjugation kits are designed for IgG1 antibodies with a molecular weight of ~150 KDa. However, our protein-drug conjugation kits can often be modified for nanobodies. For nanobodies with a molecular weight of ≤20 KDa, customization may be needed. We can also provide custom conjugation services to prepare an initial batch of your nanobody-drug conjugate and develop a kit for future use.
What concentration should I use for ADC controls (e.g., CM51100, CM51101, CM51102, CM11429) in my model?
As a general rule, the control concentration should match the drug concentration of your binding ADC (considering the DAR). For cell viability studies, use a range from 0.001 µg/mL to 10 µg/mL. Keep in mind that these non-binding ADC controls may cause non-specific cell death. For a linker-only negative control, consider conjugating your antibody with a VC-PAB linker without the toxin, or use our control kit (CM11429) for a binding antibody without the toxin.
Is it acceptable to use a Nanodrop for ADC concentration measurements?
Typically, traditional UV measurement using a UV cuvette (1 cm path length) is preferred. Some customers use Nanodrop, though we have not formally tested its accuracy. For Nanodrop, zeroing at 248 and 280 nm may improve measurement accuracy.
Do you have an ADC kit for antibody conjugation with Mc-VC-PAB-SN38?
We currently do not offer a kit for Mc-VC-PABC-SN38, as SN38 is highly hydrophobic, making the direct use of VC-PAB challenging. However, our proprietary AqueaTether® (AqT®) linker can enhance SN38’s water solubility with the VC-PAB-SN38 configuration. For further information, please check out AqT® ADC development. Additionally, we offer a Deruxtecan conjugation kit (Cat# CM11431) on our website, as Deruxtecan has a structure similar to SN38 with a cleavable peptide linker.
What antibody characteristics contribute to ADC aggregation, and can they be anticipated in advance?
Aggregation issues primarily arises from the hydrophobicity of the drugs being used, with the properties of the antibody playing a secondary role. The hydrophobicity of an antibody is complex and depends on various factors, such as the percentage and location of hydrophobic amino acids, as well as the antibody’s glycosylation. The simplest way is to assess this is to perform Hydrophobic Interaction Chromatography (HIC) on the antibody and compare its profile to that of other therapeutic antibodies, such as Herceptin.