Jackson Immuno Research Inc.
specializing in secondary antibodies and conjugates

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Secondary Antibodies

For VHH Discovery

Anti-Alpaca IgG, Subclass and VHH domain secondaries
  • Ideally time PBMC harvest
  • Enhance detection of VHH antibodies
  • Test for VHH expression and binding activity

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Whole IgG Affinity-Purified Secondary Antibodies

"I have used a wide variety of secondaries and Jackson ImmunoResearch has consistently been the best. The fluorophores are bright and stable and their selective (x reactivity removed) secondaries have always shown species specificity in multiple labeling."

Janet Duerr, Ohio University

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Secondary Antibody FAQs

Frequently Asked Questions




Customer Service and
Technical Service Phone:
800-367-5296 or 610-869-4024

(Between 8:30am and 5:00pm Eastern Time)

Customer Service fax:
610-869-0171
Customer Service email:
cuserv@jacksonimmuno.com
Technical Service email:
tech@jacksonimmuno.com


See our Contact Us page for additional contact methods.



You can place an order by any of the methods below. It will expedite your order if you can provide the following information:

  • Name
  • Telephone, Fax, and/or email
  • Customer account number
  • Institution or company name
  • Shipping and billing addresses
  • Purchase order number
  • Product code number and description (to avoid ambiguous descriptions, please see complete product descriptions for ordering purposes)
  • Quantity, size, and price

Online: www.jacksonimmuno.com (for USA & Europe)
See our distributors page for other regions.
Phone: 800-367-5296 or 610-869-4024
email: cuserv@jacksonimmuno.com
Fax: 610-869-0171
Mail: 872 West Baltimore Pike, West Grove, PA 19390


An order can be tracked on the UPS or FedEx website using the tracking number printed on the invoice. if the tracking number is not known, contact Customer Service and provide one of the following: PO number, JIR order reference number, web order number, or customer account number.



We accept payments by credit card, check, ACH, and wire transfer. Payment is due in U.S. Dollars, net 30 days from the invoice date. Any alternative terms of payment are to be agreed on prior to order placement.



Orders are shipped at ambient temperature by FedEx or UPS 2-day service unless otherwise requested. Shipping charges are prepaid F.O.B., West Grove, PA, and added to your invoice. Flat rate shipping charges apply only to the contiguous 48 states.

FedEx Economy (2-Day) $10.00
FedEx Priority $25.00
FedEx Standard Overnight $20.00
UPS Blue (2nd Day Air) $8.00
UPS Red (Next Day Air) $15.00


Alternatively, customers may use a preferred carrier collect number for shipping costs if requested at the time of order.



All returns must be pre-authorized in order to receive proper credit. Contact Customer Service 800-367-5296 for authorization to return products. We reserve the right to impose handling and restocking charges on any products returned due to customer error.



Order Value

The following discounts are automatically given for orders placed within the United States only. Orders placed outside the U.S. are not given these discounts by our international distributors due to extra costs incurred in marketing and bringing products into their countries.

Discount Order Value
5% $500 - $1,000
10% $1,001 - $1,500
15% $1,501 - $2,000
20% over $2,001

New Customers

We offer a 20% discount on the first order received from educational institutions. If the initial order is over $2,000, the discount increases to 25%. Read more about our New Lab Start-up discount here, or Contact Customer Service (800-367-5296 or cuserv@jacksonimmuno.com) to check your eligibility.



We have established a world-wide network of distributors and a European subsidiary, Jackson ImmunoResearch Europe Ltd. For international orders please contact the Jackson ImmunoResearch distributor in your area.



We do not offer sample sizes of products. Please contact Technical Service tech@jacksonimmuno.com if you have questions on product selection or usage prior to purchase.



We manufacture and supply most standard inventory secondary antibodies in bulk volumes upon request. Contact Customer Service cuserv@jacksonimmuno.com for a bulk quantity inquiry.

More information on our capabilities, including our ISO 9001:2015 certification can be found on our Bulk Service page.





View or print from the ISO certification page.



Go to the GHS/SDS search page or download from the applicable product page.



Go to the specification sheet search page or download from the applicable product page.



No, the only supporting document provided is the Product Specification Sheet.



Yes, each product page has an Images & References section which displays product citations.



Animal health certificates are available on request at tech@jacksonimmuno.com. Please inquire by product code number.



To receive a catalog in the mail, complete the request form.



Yes, stability memos can be provided on request. Please send an email to Technical Service at tech@jacksonimmuno.com.



Customer Service can provide the date of manufacture for any specific lot number. Contact customer service at 800-367-5296 or cuserv@jacksonimmuno.com for more information.





Customer Service can provide the date of manufacture for any specific lot number. Contact customer service at 800-367-5296 or cuserv@jacksonimmuno.com for more information.



Jackson ImmunoResearch uses the Biuret assay to determine protein concentration.

If protein concentration is obtained by using the mass extinction coefficient of 1.4 for a 1 mg/ml solution at OD280, the result will be 10-15% lower than the concentration obtained by the Biuret assay.



Jackson ImmunoResearch does not determine molecular weights by analytical methods. An approximate molecular weight of 160, 110 and 50 kDa can be used for whole IgG, F(ab')2 and Fab fragment antibodies, respectively. To obtain an estimated molecular weight of any other product of interest, please contact Technical Service at tech@jacksonimmuno.com.



For purchase of OEM products that have custom specifications (e.g. custom adsorptions, conjugations), please contact Technical Service at tech@jacksonimmuno.com. Jackson ImmunoResearch does not provide polyclonal or monoclonal antibody development or production services.



Jackson ImmunoResearch does not assay products for endotoxin content. For applications requiring low endotoxin consider using an endotoxin removal column, available from Thermo Fisher, Charles River Laboratories, and other suppliers.



For products that are sold by weight (mg), Jackson ImmunoResearch fills vials with slightly more product that the nominal mg amount ("Size" on the spec sheet). To calculate the actual product amount in a vial, multiply the protein concentration indicated on the spec sheet by the volume of dH2O needed to rehydrate the lyophilized pellet.





The antibodies can be diluted in buffers such as PBS or TBS. A detergent such as Tween 20 (0.05% v/v) can be included to reduce non-specific binding. We recommend making the working dilution fresh on the day of use. Carrier proteins such as BSA or normal serum are not necessary, and in some cases can increase background staining due to protein-protein interactions.

Read more about diluents in our guide to blocking, controls and diluents.



For most applications, we recommend blocking with normal serum (5% v/v) from the same species as the host of the secondary antibody. Other commonly used reagents such as BSA and non-fat dry milk are suitable for some applications, but may increase background if the secondary antibody is directed against goat, sheep, or horse.

Read more about blocking in our guide to blocking, controls and diluents.



Incubation times of 30-60 minutes are recommended for surface interactions such as ELISA or Western blotting. For staining tissue, incubation times should be increased as necessary to allow for tissue penetration. Total wash time should be approximately equal to incubation time to allow unreacted antibody to diffuse out.



Some detergents that are commonly used for permeabilization are Triton X-100, saponin and Tween 20. The optimal concentration for the chosen detergent should be established empirically.



Different fixation protocols may alter antigenic sites and make them more or less accessible to primary antibodies. If the antigenic site is available and the primary antibody binds to it, the secondary antibody will bind to the primary.



There are many commercially available substrates for development of peroxidase or alkaline phosphatase signal, and they are all compatible with the corresponding Jackson ImmunoResearch enzyme conjugate.

More information about chromogenic substrates is available on our blog page.





Immunoglobulin classes (IgA, IgD, IgE, IgG, IgM in mammals) are defined by the structure of their heavy chains. Minor differences on heavy chains are found between subclasses of each class. Jackson ImmunoResearch offers polyclonal antibodies that are specific for mouse subclasses IgG1, IgG2a, IgG2b, IgG2c, and IgG3. We also have antibodies that are specific for camelid subclasses IgG 2+3. We currently do not have subclass-specific antibodies against other species.

Download Immunoglobulin Structure and Function Poster.



These products are the result of proteolytic digestion of IgG. Digestion with papain results in Fab and Fc fragments, and digestion with pepsin yields F(ab')2 fragments.



Isotypes are distinct forms of antibody heavy and light chains, and may refer to class or subclass. Light chain isotypes are kappa and lambda, and heavy chain isotypes are alpha (IgA), delta (IgD), epsilon (IgE), gamma (IgG), mu (IgM). The heavy chains may be further differentiated as subclasses, e.g. gamma 1 (IgG1).



Isotypes are distinct forms of antibody heavy and light chains, and may refer to class or subclass. Light chain isotypes are kappa and lambda, and heavy chain isotypes are alpha (IgA), delta (IgD), epsilon (IgE), gamma (IgG), mu (IgM). The heavy chains may be further differentiated as subclasses e.g. gamma 1 (IgG1).

An isotype control is a negative control that verifies specific binding of either a primary or secondary antibody. The isotype control is the same class or subclass as the experimental antibody, but is not specific for the antigenic target. Isotype controls may be purified IgG from normal serum of the species host of the experimental antibody; or in the case of monoclonal antibodies may be monoclonals of the same subclass, directed against an irrelevant antigen. Isotype controls for unlabeled antibodies are unlabeled, and controls for labeled antibodies are labeled with the same reporter molecule (fluorophore, enzyme, or biotin) as the experimental antibody.

Read more about isotype controls in our guide to blocking, controls and diluents.





There are many factors that can influence secondary antibody selection. Read our guidelines to a systematic approach.



Choice of fluorescent probes depends on instrumentation capabilities, multiple labeling considerations, and brightness required.



Products described as Anti-IgG (H+L) contain antibodies that recognize epitopes on both the heavy and light (H+L) chains of IgG. See our guidelines for secondary antibody selection.



Some antibodies are designated "ML" to emphasize their usefulness in multiple labeling, in addition to single labeling. For further information see Multiple Labeling (ML) Using Labeled Secondary Antibodies.



Antibodies with "(min X ... Sr Prot)" in the description have been tested and/or adsorbed against IgG and/or serum proteins of those species indicated in the parentheses. These products are recommended for reducing tissue background and for multiple labeling primary antibodies raised in different host animals.



Most Jackson ImmunoResearch products are provided in 10 mM PO4, 0.25 M NaCl, pH 7.6. Conjugated products may include sodium azide and/or BSA stabilizer. For lot-specific information, consult the Product Specification Sheet for a particular product.



There is a 6-atom spacer positioned between biotin and the protein to which it is conjugated.



Aliquot in amounts that are convenient for the intended application. Aliquots stored at -70⁰C should not be subjected to multiple freeze-thaw cycles, so small volumes are recommended. Products stored as liquids (at 4⁰C, or stored at -20⁰C in 50% glycerol) can be aliquoted in multiple-use volumes.



To block whole IgG primary and secondary antibodies from binding to Fc receptors, incubate cells in buffer containing 5% normal serum from the host species of the secondary antibody. To prevent capping, endocytosis, and regeneration of Fc receptors on living cells, incubate at 4°C in buffer containing 5% normal serum with sodium azide added to inhibit metabolism.



Jackson ImmunoResearch offers monovalent Fab fragments of secondary antibodies that can be used to block endogenous immunoglobulins, obscuring them from labeled secondary antibodies used in subsequent steps.



Jackson ImmunoResearch provides several strategies for accomplishing this labeling, all of which involve monovalent Fab fragments. Multiple protocol examples are available for sequentially labeling primary and secondary antibodies. Alternatively, primary antibodies can be labeled in solution with Fab fragment anti-Fc secondary antibodies prior to incubation.



Jackson ImmunoResearch’s polyclonal secondary antibodies are routinely tested against native proteins that exhibit folded epitopes. In addition, we frequently probe Western blots of denatured and reduced immunoglobulins and find the secondary antibodies have good reactivity to these proteins.



Products ship at ambient temperature. On receipt, they should be stored according to recommendations on the Product Specification Sheet, typically at 4⁰C. Store liquid colloidal gold complexes at -20⁰C.



Freeze-dried product is stable indefinitely when stored in the original vial at 4⁰C. If you require an expiration date, please contact tech@jacksonimmuno.com and request a copy of our Stability Memo.



Refer to the product specification sheet or find your product on the storage recommendations page.



Jackson ImmunoResearch Laboratories provides secondary antibodies. We are not affiliated with The Jackson Laboratory that specializes in mice.






Jackson ImmunoResearch provides anti-IgG, light chain specific antibodies to avoid detection of the IP antibody’s heavy chain (50 kDa).



Anti-IgG, Fc fragment specific antibodies can be used to avoid detection of IP antibody’s light chain (25 kDa). However, sample reduction typically results in a small amount of degraded heavy chain at 25 kDa, and signal from these fragments must be blocked using FabuLight™ antibodies.




To ensure thorough coating, we suggest using 10 ug/ml protein in a high pH buffer such as 0.1 M Na2CO3/NaHCO3, pH 9.6.




In mouse on mouse staining, unwanted signal from endogenous immunoglobulins can be blocked using monovalent Fab fragments.



There are many commercially available mounting media that contain anti-fading reagents. Laboratories can also prepare anti-fade mounting media containing n-propyl gallate in-house.



Cy2 is incompatible with p-phenylenediamine, an anti-fading reagent that is found in some commercial mounting media such as Vectashield. Assure that p-phenylenediamine is not present in Cy2 mounting media.



Cyanine dyes have been shown to exhibit superior brightness and photostability in the non-polar environment of plastic mounting media.



To select fluorophores for multiple labeling, review instrument capabilities (available excitation wavelengths and emission filters). Narrow band-pass filters help separate signal from fluorophores that have overlapping emission spectra. Online tools are available to help choose fluorescent dye panels and match them with suitable filters.

Successful multiple labeling also requires the use of secondary antibodies that don’t cross-react with each other, the wrong primary antibody, or endogenous tissue immunoglobulins.




Using polyclonal secondary antibody-conjugates in immunoassays often provides enhanced signal compared to directly conjugated primary antibodies, due to multiple secondaries binding per individual primary.

F(ab')2 antibodies are ideal in flow cytometry analyses where the presence of Fc receptors may lead to background due to their binding of Fc domain in a whole IgG antibody. The binding properties of F(ab')2 antibodies are identical to those of the whole molecule.

For complex labeling panels where mixing pre-labeled primary antibodies in a single cocktail is desired, FabuLights™ (monovalent Fab anti-Fc antibodies) are well suited.



Using a directly labeled primary antibody is the best way to avoid detection of endogenous immunoglobulin when the primary antibody is from the same species as the experimental sample.

Unwanted signal from endogenous immunoglobulins can be blocked using monovalent Fab fragments if a secondary antibody is needed for detection.



An isotype control is a negative control that verifies specific binding of either a primary or secondary antibody. The isotype control is the same class or subclass as the experimental antibody, but is not specific for the antigenic target. Isotype controls may be purified from normal serum of the species host of the experimental antibody; or in the case of monoclonal antibodies may be monoclonals of the same subclass, directed against an irrelevant antigen. Isotype controls for unlabeled antibodies are unlabeled, and controls for labeled antibodies are labeled with the same reporter molecule (fluorophore or biotin) as the experimental antibody.

Read more about isotype controls in flow cytometry



To select fluorophores for flow cytometry, review the fluorescent channels available on the instrument. Online tools are convenient for helping choose fluorescent dye panels.




Jackson ImmunoResearch provides immunogold complexes in 4, 6, 12 and 18 nm sizes. For many applications, the particle size is not critical, and the reagents can be interchanged.

The 6, 12 and 18 nm sizes are recommended for multiple labeling protocols in transmission (TEM) and scanning (SEM) electron microscopy. These complexes have been subjected to density gradients to ensure uniformity of particle size. The 4 nm size can be used for single labeling in electron microscopy, but may contain non-uniform particles.

The 4 nm immunogold complexes offer the best tissue penetration and often are preferred for light microscopy (LM). The large sizes may also be suitable for LM. All immunogold reagents require silver enhancement for LM.



Store liquid colloidal gold complexes (6, 12 and 18 nm) at -20⁰C. Store lyophilize gold complexes (4 nm) at 4⁰C until they have been rehydrated.



Silver enhancement is required to observe immunogold staining using light microscopy. Follow our protocol for silver enhancement, or use commercially available reagents.



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