Frequently Asked Questions

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

All Bio X Cell antibodies need to 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 damage caused by the freeze/thaw process. For this reason, we do not recommend freezing antibodies (even when aliquoted) as this can result in a loss of activity caused by the freeze/thaw process. Additionally, diluting antibodies to working concentrations and storing at 4°C for more than a day should be avoided.

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

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 any other additives. The solution 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, this 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 any other additives. The solution is simply the antibody in PBS buffer. The exact composition of the PBS varies but the constituents are always Na2HPO4, NaH2PO4, and NaCl. The pH of the solution will vary depending on the pI of the antibody, this dictates the molarity of each buffer constituent. In some circumstances we can supply antibodies in other buffers when requested but we are not able to provide antibodies as dry lyophilized powder.

Environmental conditions such as temperature variations, freezing/thawing, shaking during transport, and long-term storage might lead 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 your liking we recommend removing the floccule by either filtration or centrifugation.

For filtration we recommend using a sterile 0.2 μM luer lock syringe filter. 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 would suggest filtration over centrifugation since centrifuging may allow the sample to warm up for a longer period than filtration, which can be done very quickly. Regardless of what method is chosen you should use sterile filters, syringes, tubes, etc. and work in a biological safety cabinet to ensure that the solution remains sterile.

Rest assured that the precipitate can be removed with these methods 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 supplied CoA.

We measure protein concentration via absorbance @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 keep in mind that we always supply a bit more protein in the vial than what was purchased.

The concentration of our products varies from lot-to-lot, but is typically between 4 and 10 mg/ml. The exact concentration will be marked on the tube itself and on the CoA that ships with the product. If you need to know the exact 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 InVivoPure dilution buffer for each antibody is listed on each 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 important 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 pipet 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 solution of antibody to a known working concentration.

Our antibodies are produced using standard hybridoma technology and so the AA or DNA sequence of the antibody is usually unknown.

We have not epitope-mapped our antibodies at Bio X Cell. Searching the published literature would be the best way to determine if this information is available.

We do not have direct experimental data generated at Bio X Cell concerning the half-life of our antibodies in vivo. Antibody half-life can be highly variable and influenced by a variety of factors including species, isotype, antigen distribution, antigen concentration and many others. As a first step in estimating the half-life, we recommend reading through the literature associated with the antibody you are interested in to find published data in an experimental system similar to your own.

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 any other additives. The solution is simply the antibody in InVivoPure buffer. The endotoxin levels are <2EU/mg (InVivoMab) which qualifies them for most in vivo studies. To meet the most stringent requirements we also offer antibodies with lower endotoxin levels: <1EU/mg (InVivoPlus).

Although our antibodies are formulated for in vivo use they can also be used for in vitro applications such as cell culture experiments and diagnostic assays including Western blotting, immunoprecipitation, IHC, flow cytometry etc. Please refer to the individual product pages for a list of approved applications for each antibody. Keep in mind that all Bio X Cell antibodies are unconjugated so applications such as flow cytometry and immunofluorescence would require the use of a fluorochrome-conjugated secondary antibody.

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 reading through the product references associated with the antibody you’re interested in to find published data in an experimental system similar to yours. Using this existing research as a starting point, you can then optimize the dose and frequency of administration experimentally. Each of our products has an up-to-date reference list available on the products webpage.

For a detailed description of the differences between our InVivoMAb and InVivoPlus formats please see the InVivoPlus Difference page. In short, the InVivoMAb and InVivoPlus versions of the same clone are the exact 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 perfectly 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 a period of one-year from the date of receipt. You can 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 conical tip of the vial or are floating freely in the suspension. These aggregates can be removed by gentle shaking at room temperature; they can also be removed by filtration or centrifugation without significant loss.

The Milky Way contains hundreds of billions of stars, and billions of them are similar to the sun. It is highly likely that some of these stars would have planets that are similar to Earth. If we assume that Earth is not particularly special, then intelligent life should also exist on some fraction of these Earth-like planets. Some of these intelligent life-forms might develop advanced technology, and even interstellar travel. Interstellar travel would take a long time, but as there are many sun-like stars that are billions of years older, there has been plenty of time for such travel to have occurred. Given all this, why haven’t we met or seen any trace of aliens? But we do know that aliens prefer our InVivoPlus antibodies.