Secondary antibodies are used to detect a primary antibody and allow for the amplification of a signal. Secondary antibodies are produced by immunizing an animal, such as a goat, with antibodies from a different species. For example, immunizing a goat with rabbit IgG will produce goat anti-rabbit IgG secondary antibodies. It is important to choose a secondary antibody that corresponds to the species in which the primary antibody was generated, as well as its isotype. For example, a goat anti-rabbit IgG secondary antibody can detect rabbit IgG primary antibodies. Secondary antibodies can be conjugated to fluorophores, such as Alexa Fluor dyes, enzymes like HRP and alkaline phosphatase, or proteins like biotin to allow detection or visualization. We offer a wide range of secondary antibodies, with over 35 conjugates to choose from, as well carrier-free secondary antibodies suitable for your own conjugation needs and Lightning-Link® kits to allow for quick conjugation with minimal antibody loss.
Alexa Fluor Secondary Antibodies →
Fluorescently Labeled Antibodies →
Secondary antibodies are commonly used tools alongside primary antibodies to allow for the detection and visualization of an antigen. Secondary antibodies are commonly conjugated to enzymes, fluorophores, tags, or other molecules to allow for detection or visualization. We offer a wide range of fluorophore-conjugated secondary antibodies covering the spectrum, allowing you to choose sets of antibodies with minimal spectral overlap. We offer a range of over 200 Alexa Fluor® conjugated secondary antibodies derived from various species, such as donkey, goat, and rabbit. The available products have unique absorption and emission characteristics, which correspond to common excitation wavelengths.
Secondary antibodies can be conjugated to enzymes like horseradish peroxidase (HRP) and alkaline phosphatase or to proteins like biotin to enhance primary antibody signals. HRP is a fast and stable enzyme widely used as an immunoassay detection reagent. Its high turnover rate allows secondary antibodies conjugated to HRP to produce strong signals rapidly. HRP substrates can be categorized as chromogenic (eg, DAB, TMB, or OPD), fluorogenic (eg, ADHP), or chemiluminescent (eg, ECL), depending on whether they generate a colored, fluorescent, or luminescent product. We offer a variety of HRP-conjugated secondary antibodies, including those targeting different species and isotypes, as well as fragment and pre-adsorbed forms. Our recommended HRP-conjugated secondary antibodies include goat antibodies reactive to mouse (IgG), rabbit (IgG), donkey (IgG), rat (IgG), and chicken (IgY), as well as rabbit antibodies reactive to human (IgG). These antibodies are available in various isotypes to suit different experimental needs with different conjugates or fluorophores.
alexa-fluor
Alexa Fluor® Secondary Antibodies
Our Alexa Fluor®-conjugated secondary antibodies deliver bright staining with minimal background, using Alexa Fluor® dyes for unmatched fluorescence intensity and minimal spectral overlap.
fluorescent
Fluorescently Labeled Antibodies
Elevate your research with our fluorescently labeled primary antibodies. With an ever-growing selection of fluorescently conjugated antibodies, we can help you with your fluorescence needs. Selecting the right antibodies and labels is key to preventing issues like cross-talk and false positives, ensuring you get precise and trustworthy results every time. Choose from our wide range of antibodies conjugated to different fluorophores and tested in numerous applications to expand the scope of your research.
conjugated
HRP Conjugated Antibodies
Horseradish peroxidase (HRP)-conjugated secondary antibodies are antibodies conjugated (chemically linked) to the enzyme HRP. Our HRP-conjugated secondary antibodies are extensively tested and optimized to ensure high specificity and sensitivity in a variety of applications. We provide HRP-conjugated secondary antibodies specific to a range of species and isotypes, with options available in fragment and pre-adsorbed formats.
unconjugated
Unconjugated Antibodies
Discover our wide selection of unconjugated antibodies and antibodies labeled with alternatives to traditional fluorescent dyes and horseradish peroxidase (HRP). Our offerings feature carrier-free formats as well as antibodies conjugated to metals, oligonucleotides, and other advanced labels. These specialized products are designed to support a variety of advanced research needs.
Features
- HRP-conjugated secondary antibodies can be used to detect low abundance targets with excellent signal-to-noise ratios due to the optimal number of HRP molecules per antibody.
- Our HRP-conjugated secondary antibodies maintain high specificity and minimal background at a range of dilutions from 1:2,000 to 1:20,000.
- Supplied in a liquid format ready for use and stable at 4°C, HRP-conjugated secondary antibodies are compatible with chromogenic, fluorogenic, and chemiluminescent substrates.
- Our Alexa Fluor® conjugated secondary antibodies offer superior fluorescence intensity compared to other similar dyes and maintain fluorescence for extended observation and imaging time.
- The optimized dye-to-antibody ratio minimizes photobleaching and ensures bright staining while each conjugate undergoes column separation to reduce background staining.
- Carrier-free secondary antibodies come with low endotoxin levels and are free from BSA and sodium azide, and are thus suitable for your own conjugation needs, providing you with the flexibility you need.
- Our Lightning-Link® kits allow for a seamless and time-saving conjugation process without the need for further purification.
Applications
Alexa Fluor® conjugated secondary antibodies can be used for:
- Cell imaging: In high-resolution fluorescence microscopy and cell imaging applications.
- Flow cytometry: For precise cell analysis and sorting.
- Fluorescence western blot: Provide clear, bright signals in western blotting for protein detection.
- Multi-color analysis: Enable effective multi-color analysis with minimal spectral overlap.
HRP-conjugated secondary antibodies can be used for:
- Western blot: Optimized for high sensitivity and specificity in western blot applications.
- Immunohistochemistry (IHC): Provide reliable and robust detection in tissue samples through IHC.
- Enzyme-linked immunosorbent assay (ELISA): Enable accurate signal amplification and detection in ELISA.
Secondary antibodies with other conjugates:
- Several conjugate options: Over 35 conjugates to choose from
- Gold-based conjugates: Choose from several gold-based conjugates
- Custom conjugation: Abcam offers a custom conjugation service if you cannot find the right antibody-conjugate combination for your needs.
Carrier-free antibodies
- Flexibility: The carrier-free formulations are compatible with a wide range of labels, including fluorochromes, metal isotopes, oligonucleotides, and enzymes, making them suitable for diverse applications.
- Recombinantly manufactured: Our carrier-free antibodies provide exceptional batch-to-batch consistency, ensuring reliable results across experiments.
- Suitability: These products are formulated without BSA, sodium azide, or glycerol, ensuring consistent and efficient conjugation.
What are conjugated secondary antibodies?
Conjugated secondary antibodies are antibodies that are chemically linked (or conjugated) to a detectable marker, such as an enzyme (eg, horseradish peroxidase, HRP), a fluorescent dye, or biotin. These secondary antibodies bind to a primary antibody that is specific to a target protein, and the conjugated marker allows for the visualization or measurement of the target. The conjugated marker amplifies the signal, enabling the detection of low-abundance proteins in various techniques such as western blotting, immunohistochemistry, and flow cytometry.
How do I select a fluorescently labeled secondary antibody for flow cytometry?
To select a fluorescently labeled secondary antibody for flow cytometry, choose one that is conjugated to a fluorophore with an appropriate excitation and emission spectrum that matches your flow cytometer’s available lasers and detectors. Ensure the secondary antibody is specific to the host species of your primary antibody, and select one with minimal spectral overlap if using multiple colors for multi-parameter analysis. Additionally, consider the antibody’s sensitivity, brightness, and photostability to ensure strong, reproducible signal detection.
How do anti-mouse and anti-rabbit secondary antibodies differ?
Anti-mouse and anti-rabbit secondary antibodies differ in their specificity; anti-mouse secondary antibodies are designed to bind to mouse primary antibodies, while anti-rabbit secondary antibodies bind to rabbit primary antibodies. Each type is tailored to recognize the immunoglobulin G (IgG) or other isotypes from their respective species, enabling precise detection in experiments.
What is the role of HRP and alkaline phosphatase in secondary antibodies?
HRP and alkaline phosphatase are enzymes often conjugated to secondary antibodies to produce a signal using chromogenic substrates in detection assays. When exposed to their respective substrates, HRP catalyzes a colorimetric or chemiluminescent reaction, and alkaline phosphatase produces a colorimetric or fluorescent signal, enabling the visualization of the primary antibody binding to the target antigen.