Antibody FAQs

General questions

  • Does Sino Biological produce antibodies in house?

    Yes. Sino Biological Inc. has extensive experience in generating high quality antibodies by our proprietary platform. We have successfully developed thousands of antibodies against a variety of targets including but not limited to viruses, drug targets, CD molecules, cytokines and enzymes. All these antibodies are made in house and our antibody team strives to only deliver antibodies meeting our strict QC criteria to customers.

  • How does Sino Biological ensure the quality of antibody products?

    Sino Biological got the ISO9001 quality system certification since 2010. Due to all antibody products are self-developed, antibody quality can be strictly monitored from upstream to downstream with uniform standards. We have already built internal quality control system for antibodies including all major applications (WB, ELISA, flow cytometry, immunofluorescence, immunohistochemistry and immunoprecipitation). All products on shelves are carefully selected through several rounds of screening from dozens of candidates. Finally, only the best one for each application is selected for sale. Except special products (such as antibodies against virus), all antibodies are validated using natural tissues or cells to ensure the best performance in the detection of endogenous targets. In addition, we take strict release tests for each batch of product to control the variation due to the production.

  • How does Sino Biological make mass production of monoclonal antibodies? Do you use in vivo ascite production?

    We never perform ascite production. All our monoclonal antibodies are produced in vitro based on advanced mammalian cell culture technology. It not only eliminated the animal welfare problems (ascite production is prohibited in some countries) but also ensured the better antibody quality due to the less potential contamination from animals and lower variations from batch to batch.

  • Is there any patent conflict with other companies in development of rabbit monoclonal antibody? What are the differences between Sino Biological and other vendors in antibody technology and products?

    Sino Biological developed a secondary generation of rabbit monoclonal antibody technology based on antibody library instead of patented rabbit hybridoma. Therefore, there is no patent conflict issue.

    We produce rabbit antibodies using serum-free media and large scale cell culture technique which have high yield and much less variation batch to batch. In addition, we are different from the rest of rabbit monoclonal antibody vendors in antibody purity. Although it takes more costs and time all our rabbit monoclonal antibody products are purified with protein A/G to ensure the high purity while other companies may only provide tissue culture supernatant without purification steps.

  • Why Sino Biological choose recombinant proteins instead of peptides as immunogens in development of antibodies?

    In general, antibodies made by short peptide immunogens can only recognize linear epitopes. In contrast, recombinant proteins with 3D structures and biological activity are ideal immunogens to make antibodies recognizing conformational epitopes of the targets for ELISA, FCM, IP and some IHC applications.

    For a long time, the vast majority of antibodies are produced using polypeptides due to the technical challenges and much higher costs in protein antigen production. Differed from other antibody companies, our advanced protein production platform enables us to make lots of antibodies using recombinant proteins with affordable price. Furthermore, 90% of these protein immunogens are from eukaryotic expression systems and have the very similar modification and structure to the natural targets. It is very important to help us make the best antibodies for your applications.

  • Do you update the information of antibody in data sheet or COA if there are any changes?

    Yes. All information in our data sheet except for special marks is obtained from real experiments. If there are any changes we will update the information in time.

Select Products and Place Order

  • Can I get a free sample for a trial?

    Yes, Sino Biological has free samples available from time to time in our promotion activities. Please visit frequently or contact us directly.

  • Can I get discount for Sino Biological products?

    In general, Sino Biological provides special discounts for bulk orders and some new products. In addition we have sales promotion from time to time for various antibody reagents. If you would like to get the information, please visit our website( frequently, contact our customer service (400-800-9989 - Order) or our local authorized distributers.

  • Which kinds of antibodies does Sino Biological have? How can I choose the right one?

    Sino Biological provides a wide variety of antibody products to meet different customer's requests including affinity and non-affinity purified rabbit polyclonal antibodies, rabbit and mouse monoclonal antibodies, and fluorescence or enzyme conjugated antibodies. As miscellaneous proteins existed in non-purified antibodies may affect the antibody performance in some assays we do not offer any antibody products without purification such as serum, culture supernatant or ascites.

    Sometimes Sino Biological offers more than one antibody product against the same target. You need choose the antibody to meet your experimental requirements based on antibody application, specificity, cross-reactivity, species, and immunogens. Please contact our customer service (400-800-9989 - Order) for assistance in selecting the best fit antibody for you.

  • Where can I get the reactivity of antibody with other species? How do I determine whether an antibody can be used to detect the antigen from other species?

    Due to the complex antigen structure and modification it is hard to estimate the antibody binding to the antigens from other species. Even if the sequence of antigen among different species is very similar, the recognition of the antibody is not guaranteed.

    Sino Biological's products provide some data regarding antibody cross-reactivity to determine whether such antibodies can recognize protein isoforms ,other members in the same superfamily and target antigen from other species. Please note, however, that the data for cross-reactions are mostly obtained by ELISA, they may not apply to other applications such as Western Blotting and IHC.

    If you could feedback relevant results of antibody in untested species to Sino Biological (either negative or positive), we will provide you a special promotion or award. Of course, in order to enhance the possibility for unknown species, comparison of the amino acid sequence between immunogen and the tested target is recommended.

  • Does Sino Biological provide antibodies with multiple applications?

    For the same antigen, more than one application is required for the corresponding antibody by some customers. Based on Sino Biological antibody screening strategy, for each application, only the best one is for sale. Since different applications have their specific requirements to the antibodies it is hard to find the antibodies meeting all applications. However, we do have some antibodies with more than one application and will try our best to provide more and more multi-functional antibodies in the future.

  • Will Sino Biological Inc.'s antibody work in an application that is not listed in the applications table?

    Customers can find all the tested applications for each particular antibody by visiting Sino Biological Inc. Antibody website. We do not list any untested applications. We would greatly appreciate it if you would test our antibody in an unproven application and share the results with us. We will issue you credits or awards in return for your data.

  • What is the particular monoclonal antibody epitope? Is the antigen sequence provided?

    Many of our antibodies are produced using recombinant proteins, so it is hard to identify the specific epitope of the monoclonal antibody. The catalog number of the recombinant protein used as the immunogen is listed on the Certificate of Analysis. For the monoclonal antibodies obtained using peptides as antigens, an epitope range recognized by corresponding antibody will be provided.

  • Is rabbit monoclonal antibody better than mouse monoclonal antibody?

    The affinity of rabbit monoclonal antibody is 10-100 times higher than that of mouse antibody. Rabbit monoclonal antibody is highly recommended if you have following requirements:

    • Need excellent performance in immunohistochemistry or Western blotting applications;
    • Requirement in detection of targets with low expression level;
    • Develop ELISA assays with other mouse monoclonal antibodies.
  • How can I select the right secondary antibody for my experiment?

    In general, secondary antibody refers to it can bind to primary antibody and is labeled with a marker or dye (e.g. fluorescent dye, radioactive molecule, chemiluminescent, or chromogenic groups). With secondary antibody, the signal can be amplified for detection. We suggest you consider the following factors:

    1. Depending on the host species. For example, if the primary antibody is from rabbit, the secondary antibody should be anti-rabbit.
    2. Depending on the characteristics of primary antibody. If the primary antibody is a Fab fragment, you can only select the anti-Fab fragment secondary antibody or anti-full length secondary antibody products, but not anti-Fc fragment secondary antibody.
    3. Depending on your applications, such as WB, IHC, ELISA, etc. Please refer our data sheet to confirm the secondary antibody tested for the related applications. Currently, Sino Biological provides HRP, biotin and fluorescent dye-labeled secondary antibody. The secondary antibody with more labels will be on our list soon.

  • What is the antibody clone ID? What is the difference between clone ID and lot number?

    Antibody clone ID is the internal unique identity number assigned to each monoclonal antibody clone while lot number is corresponding to each batch of antibody mass production. The antibodies with same clone ID but different lot numbers have no difference in general.

  • What materials are provided in your ELISA Kit and ELISA pair sets?

    Currently our ELISA pair sets contain the capture antibody, the detection antibody, and the standard (recombinant protein). Other buffer solutions and substrate stock solutions required for the development of sandwich ELISAs need to be prepared by customers. In contrast, our complete ELISA kits provide all above reagents and are ready to use for your ELISA experiments.

  • Could Sino Biological develop an antibody for me if I do not find the suitable catalogue products?

    Yes. Sino Biological provide one-stop antibody services for all steps of antibody development and production, including peptide and recombinant protein antigen preparation, animal immunization, mouse hybridoma fusion, rabbit polyclonal and monoclonal antibody development, antibody production from mg to 100 grams, and comprehensive antibody validations for multiple applications. Please call us or send an email to for more information.

  • Can I ask for a replacement or refund for your antibody products?

    Sino Biological is committed to provide high quality products. If you find quality problems, the products can be replaced for free or you will get a full refund. However, if the antibody used in untested species or application, we can not provide a replacement or refund. Please read the product description or contact our customer service staff carefully before purchase.

Application Guide

  • What concentration of primary antibody should I use? How to determine the suitable dilutions of antibodies?

    The recommended starting dilutions or working concentration can be found in our product data sheet and COA. However, optimal dilutions/concentrations should be determined by the end user as different detection devices, methods and samples all have significant influence on it.

  • How can I choose an isotype control antibody?

    Isotype control antibody is used to confirm that the primary antibody binds to the target due to the specific antibody-antigen interaction but not Fc receptor or non-related protein bindings. Therefore, isotype control antibody should match the primary antibody's host species, subtypes and conjugations. For example, if the primary antibody is a mouse IgG1 with FITC conjugated, the isotype control needs to select FITC conjugated mouse IgG1.

  • How can I choose a positive control?

    If you need an appropriate positive control, we currently offer more than 4000 over-expressed cell lysates for Western Blotting. The target protein expression is verified by protein purification from the cell lysates. Please refer to our protein data sheet for relevant information.

    Please note that some of our over-expressed proteins are not the full-length, especially for multiple transmembrane proteins. Please refer our data sheet to make sure that the epitope of antibody you used is within the range of protein sequences.

  • What kinds of loading control (internal control) should I use in Western Blotting (WB)?

    The antibodies against tubulin, beta-actin or GAPDH are commonly used in Western Blotting as loading controls for quantitative analysis of the samples due to their stable expression level in most of cases. The following two factors need be noted in the selection of suitable loading controls in your experiments:

    1.Type of cell lysates: choose the loading control targets existed in lysates. For example, as the tubulin and actin are located in cytoplasm the corresponding antibodies could not be used in western blotting with nuclear cell lysates (please choose histone antibody in this case).

    2.Molecular weight: It is important that the protein chosen as a loading control has a different molecular weight than the tested protein target to avoid the interference between both bands. For example, if the target is about 39 kDa it is better to choose tubulin antibody instead of actin antibody as loading control since the molecular weight of these two proteins are 50kDa and 42kDa respectively.

    Please see our loading control list to find the suitable antibodies.

  • Why is the actual band size different from the predicted?

    Protein migration in the gel is affected by many factors so the actual band size observed may differ from that predicted. The common factors include:
    1. Post-translational modification - e.g. phosphorylation, glycosylation etc. which increases the size of the protein
    2. Post-translation cleavage - many proteins are synthesized as pro-proteins, and then cleaved to give the active form, e.g. pro-caspases
    3. Splice variants - alternative splicing may create different sized proteins from the same gene
    4. Relative charge - the composition of amino acids (charged vs. non-charged)
    5. Multimers - e.g. dimerisation of a protein. This is usually prevented under reducing conditions.

  • What is the antigen retrieval method used for Sino Biological's IHC antibodies?

    Sino Biological use microwave for antigen retrieval in IHC application. The tissue slices are heated 5 × 2 min in a microwave oven with maximum power in 0.01M citrate buffer (pH 6.0) (heating time may extend to 15 min for certain antigens).

  • Does Sino Biological antibodies with ELISA application work for "sandwich" ELISA?

    All our ELISA antibodies could recognize the corresponding antigens coated in the plates. The antibody with high sensitivity in direct ELISA may not be chosen as the final capture or detection antibody in sandwich ELISA assays due to multiple factors including the non-specific interaction between capture and detection antibodies, failure after enzyme conjugation, bad stability and so on.

    Sino Biological offers many paired antibodies (ELISA pair sets and Kits) as well as complete ELISA kits. Please first check our product lists if you would like to develop a sandwich ELISA assay.

  • Are the Sino ELISA kits validated by natural samples?

    Most of the ELISA kits are tested by natural samples such as serum and the relevant data are listed in the manual. Due to no relevant information available or reported, a few kits are tested by recombinant proteins only. If you could feedback your positive ELISA results of natural samples which we do not test yet to Sino Biological, we will provide you a special promotion or award.

  • What is trehalose?Why trehalose is included in antibody formulation?Does this reagent affect my experiment?

    Trehalose is a non-reducing saccharide composed of two glucose molecules. It can form a unique protective film on surface of protein and protects the stability of protein at low or high temperature, high osmotic pressure, dehydration and other harsh environmental conditions. It has been widely used in protein drugs, enzymes, vaccines and other biological products. Some of antibody products from Sino Biological also contain such component to ensure the antibody's activity and stability. Under normal circumstances, this component does not affect your experiment results. If you have any questions, please call 400-800-9989 or send an email to

  • Does the antibody buffer contain preservatives?

    All of our non-labeled antibodies have no preservatives except special comments. Although stability of the antibody is guaranteed at 4 ℃ within a month, there is a risk of microbial contamination. It is recommended to add some preservatives if you need to store the products at 4 ℃.
    HPR and the fluorescent-labeled antibodies contain preservatives and can be stable for one year at 4 ℃. Please refer the instruction of each antibody.

Shipping and storage

  • How long can I get the products after I place an order?

    Most of our antibody products are in stock and upon the receipt of payment or formal purchase order (PO), the items will be shipped out within 1-3 business days. In most areas of the world our customers can receive ordered products within 1 week. Please contact our customer service to know the delivery time in your area,

  • Why do most your antibody products ship at room temperature?

    All of our antibody products are commonly shipped at room temperature to save your shipping cost and reduce environment pollution caused by packing materials waste. It remains stable during the delivery process at ambient temperature. We have tested antibody's stability and activity following a period of more than 7 days at -20°C, room temperature, or 37°C. Antibodies under all three conditions turned out to be equally active and stable. For detailed information, please go to: Antibody Stability. If you have any other special requirements, we provide a variety of shipping methods with extra costs.

  • How should I store the antibody?

    Please follow the recommended methods listed in the instructions. Otherwise, the quality of antibodies can not be guaranteed. Aliquots are recommended to avoid repeated freeze and thaw cycles.

  • How should I aliquot antibodies?

    Please aliquot antibodies according to the amount used in your experiment, but each aliquot should not be less than 10 μL. The less amount of each aliquot, the greater impact is on antibody concentration due to liquid evaporation and container adsorption.

  • What is the shelf life of Sino Biological Inc.'s antibodies?

    Unless indicated in the data sheet, most of our non-labeled antibodies can be stored at 2℃-8℃ for one month without detectable loss of activity and are stable for twelve months from date of receipt when stored at -20℃ to-80℃. Repeated freezing and thawing should be avoided.

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