Frequently Asked Questions

To avoid contamination, always maintain the antibodies’ sterility. Only open the antibody vial in a biological safety cabinet, and always use sterile pipette tips, tubes, syringes, and buffers to manipulate the antibody solution. These precautions will significantly reduce the chances of contamination. Additionally, try to keep the antibodies cold until just before administration.

All Bio X Cell antibodies must be stored at the original stock concentration at 4°C. Since our antibodies are formulated for in vivo use, they contain no stabilizers, carrier proteins, glycerol, or other protection against freeze/thaw damage. Therefore, we do not recommend freezing antibodies (even when aliquoted), as this can result in a loss of activity caused by the freeze/thaw process. We do not recommend diluting antibodies to working concentrations and storing them at 4°C for more than one day.

Bio X Cell’s products have a minimum guaranteed shelf life of one year from the date of customer receipt. Please see further details within Bio X Cell’s performance guarantee.

A lot-specific certificate of analysis (CoA) can be generated using our CoA generator. 

Our antibodies are only available in a liquid solution. We are not able to provide antibodies as a dry or lyophilized powder. All antibodies are formulated in sterile InVivoPure™  buffer. The concentration of our antibodies varies from lot to lot but generally ranges from 4 to 11 mg/ml.

The antibody solution contains no stabilizers, preservatives, carrier proteins, glycerol, or other additives. It is simply the antibody in InVivoPure™ buffer. The exact composition of the InVivoPure™ buffer varies, but the constituents are always Na2HPO4, NaH2PO4, and NaCl. The pH of the solution will vary depending on the pH of the antibody, which dictates the molarity of each buffer constituent.

Our antibodies are supplied in sterile PBS buffer. The solution contains no stabilizers, preservatives, carrier proteins, glycerol, or other additives. The exact composition of the PBS varies depending on the antibody’s pI, but the constituents are always Na2HPO4, NaH2PO4, and NaCl. In some circumstances, we can supply antibodies in other buffers, but we cannot provide antibodies as dry lyophilized powder.

Environmental conditions such as temperature variations, freezing/thawing, shaking during transport, and long-term storage might lead to the appearance of a precipitate or floccule in the antibody solution. This is not uncommon. The floccule is typically buffer salts precipitating out of solution or a small bit of protein aggregation. If gentle, repeated inversion of the vial does not remove the precipitate to an acceptable degree, we recommend removing the floccule by either filtration or centrifugation.

We recommend using a sterile 0.2 μM Luer Lock syringe filter for filtration. For centrifugation, we recommend transferring the antibody solution to a sterile centrifuge tube (do not centrifuge in the provided cryo vial) and centrifuging at 10k rpm for 5 minutes. We suggest filtration over centrifugation since centrifuging may allow the sample to warm up for a more extended period than filtration, which can be done very quickly. Regardless of the chosen method, you should use sterile filters, syringes, tubes, etc., and work in a biological safety cabinet to ensure the solution remains sterile.

These methods can remove the precipitate without significant protein loss. If you are concerned about loss after centrifugation or filtration, you can check the protein concentration after these processes and compare it to the concentration on the supplied CoA.

We measure protein concentration via absorbance at 280 nm using an extinction coefficient of 1.33. When determining the concentration of our products, we first mix 100 μL of the stock antibody solution with 1.9 mL of pH-matched PBS (1:20 dilution). We then take the A280 reading (after the spec has been blanked against our pH-matched PBS), multiply it by 20 (as this is our dilution factor), and then multiply by 0.75 (which is the result of 1/1.33). Please remember that we always supply slightly more protein in the vial than what was purchased.

The concentration of our products varies from lot to lot but is typically between 3 and 12 mg/ml. The exact concentration will be marked on the tube and the CoA that ships with the product. If you need to know the precise concentration of a product before ordering, please contact technicalservice@bioxcell.com.

We recommend diluting our antibodies in the InVivoPure™ dilution buffer matching the pH that the antibody is supplied in. The recommended InVivo Pure™ dilution buffer for each antibody is listed on its product page. In the absence of the recommended InVivoPure™ dilution buffer, sterile 1x PBS matching the exact pH of the antibody formulation can be used. It is essential to match the pH of the dilution buffer to the antibody solution to avoid aggregation.

When diluting, we recommend using cold buffer and maintaining sterility by working in a biological safety cabinet and using sterile pipette tips, tubes, syringes, and buffers.

Diluting antibodies to working concentrations and storing at 4°C for more than a day should be avoided.

You can use our Dilution Calculator to calculate how to dilute a stock antibody solution to a known working concentration.

Our antibodies are produced using standard hybridoma technology; therefore, the AA or DNA sequence of the antibody is usually unknown.

Bio X Cell has not epitope-mapped our antibodies. The best way to determine if this information is available is to search the published literature.

Bio X Cell does not generate direct experimental data to determine the half-life of our antibodies in vivo. Antibody half-life can be highly variable and influenced by various factors, including species, isotype, antigen distribution, antigen concentration, and many others. As a first step in estimating half-life, we recommend reviewing the literature associated with the antibody you are interested in to find published data in an experimental system similar to yours.

All of our products are formulated specifically for in vivo use. All antibodies are formulated in sterile InVivoPure™ buffer. The antibody solution contains no stabilizers, preservatives, carrier proteins, glycerol, or other additives. The solution is simply the antibody in InVivoPure™ buffer. Our InVivoMab™ antibodies have ≤1EU/mg endotoxin levels, qualifying them for most in vivo studies. We also offer InVivoPlus™ antibodies with lower endotoxin levels: ≤0.5EU/mg to meet the most stringent requirements.

Although our antibodies are formulated for in vivo use, they can also be used for in vitro applications such as cell culture experiments and immunoassays, including Western blotting, immunoprecipitation, IHC, flow cytometry, etc. Please refer to individual antibody product pages for a list of approved applications. For applications that require a fluorophore-conjugated antibody, explore our FlowMAb™ product line.

The optimal dose and frequency of administration for any given experiment and antibody can vary greatly depending on the experimental system (i.e., mouse strain, disease model, etc.), the duration of the experiment, the target tissue, the antigen concentration, and many other details. For this reason, the optimal dose is best determined by reviewing the product references associated with the antibody of interest to find published data in an experimental system similar to yours. Using existing research as a starting point, you can then optimize the dose and frequency of administration experimentally. Our products all have an up-to-date reference list available on the product page.

Please review the Bio X Cell Product Selection Guide for a detailed description of the differences between our InVivoMAb™ and InVivoPlus™ formats.

In short, the InVivoMAb™ and InVivoPlus™ versions of the same clone are the same antibody with the same functional properties, applications, and formulation. The difference is in the quality control (QC) included. The InVivoPlus™ version is validated for antigen binding, screened for murine pathogens, and screened for aggregates, while the InVivoMAb™ version is not. Both the InVivoMAb™ and InVivoPlus™ formats are well suited for in vivo use; it is just a matter of whether you need additional QC measures.

Please see our guide to choosing an anti-PD-1 antibody.

Incorporating an isotype control-treated group is required to generate reliable data because it allows the researcher to accurately differentiate between results observed from primary antibody binding in an antigen-specific manner and results observed from non-antigen-specific binding or other nonspecific effects of antibody injection. The isotype control antibody must match the host species, isotype, and subclass of the primary antibody. For the convenience of our customers, we have listed the recommended isotype control antibody for all of our primary antibodies on each product page. For more information on isotype controls, please see our guide to selecting an isotype control antibody.

All Bio X Cell products are guaranteed to function for the reported applications listed for one year from the date of receipt. View our guarantee. If you suspect that your antibody is not functioning optimally, please fill out and submit a technical service request form.

Environmental conditions such as temperature variations, freezing/thawing, shaking during transport, or long-term storage might lead to protein aggregation. These aggregates are either settled in the vial’s conical tip or floating freely in the suspension. They can be removed by gentle shaking at room temperature, filtration, or centrifugation without significant loss.

Environmental conditions such as temperature variations, freezing/thawing, shaking during transport, or long-term storage might lead to the appearance of a precipitate or floccule in the antibody solution, which is not uncommon. The floccule is typically buffer salts precipitating out of solution or a small bit of protein aggregation. If gentle, repeated inversion of the vial does not remove the precipitate to your liking, then we recommend removing the floccule by either filtration or centrifugation.

We recommend using a sterile 0.2 μM Luer Lock syringe polyethersulfone (PES) filter for filtration. For centrifugation, we would recommend transferring the antibody solution to a sterile centrifuge tube (do not centrifuge in the provided cryo vial) and centrifuging at 10k rpm for 5 minutes. We suggest filtration over centrifugation since centrifuging may allow the sample to warm up for a more extended period than filtration, which can be done quickly. Regardless of the chosen method, you should use sterile filters, syringes, tubes, etc, and work in a biological safety cabinet to ensure the solution remains sterile.

These methods can remove the precipitate without significant protein loss. If you are concerned about loss after centrifugation or filtration, you can check the protein concentration after centrifugation or filtration and compare it to the concentration on the vial label. We measure protein concentration via absorbance at 280 nm using the extinction coefficient noted on the CoA.