Research Antibodies: Primary, Secondary, and Specialised Formats

Primary and secondary antibodies validated for reliable immunoassay detection

Every immunoassay depends on two choices: the primary antibody that binds your target, and the secondary antibody that delivers the detection signal. Getting these two choices right sets up the rest of your protocol.

Primary antibodies come as monoclonal or polyclonal formats. They are available across host species including rabbit, mouse, and goat. Monoclonal antibodies offer consistent epitope specificity and lot-to-lot reproducibility, so you can expect a consistent signal in western blot and IHC.

Polyclonal antibodies typically give you a stronger signal and tolerate epitope variation better. This can help in immunofluorescence and flow cytometry. Many primary antibodies include knockout or knockdown validation data, which is strong evidence of specificity for your target. This validation is application and context specific, so orthogonal methods and application-specific controls are still recommended. Antibody pair sets package matched capture and detection antibodies together, giving you a practical starting point for sandwich ELISA development.

Secondary antibodies complete the detection chain. Affinity-purified formats are available with HRP, fluorophore, and biotin conjugates, covering the standard pairings you need for western blot, ELISA, and fluorescence-based applications. Pre-matched antibody bundles combine primary and secondary pairs. They reduce optimisation time when you need a validated panel for a defined set of targets.

The sub-category links below take you to primary or secondary antibodies directly, and the search page lets you filter by host species, clonality, application, and label.

Finding an antibody that will work in your assay

1. Target. The exact protein name comes first, along with the specific isoform or post-translational modification you need to detect, where relevant. This first step makes sure you are targeting the right protein.

2. Species reactivity. The antibody needs validation to recognise the protein in the species you work with, for example human, mouse, or rat. Species reactivity depends on sequence homology around the epitope. The datasheet or validation data confirms this.

3. Application. An antibody validated for western blot may perform poorly in immunofluorescence, flow cytometry, or immunohistochemistry, so application-specific validation from the supplier is worth checking before you commit to your assay. Published data helps too, where available.

4. Clonality. Monoclonal antibodies come from a single B-cell clone. They bind one epitope with high specificity and excellent lot-to-lot consistency. Polyclonal antibodies are mixtures of clones that recognise multiple epitopes on the same antigen, often giving you higher apparent sensitivity, but more variability between lots.