Monoclonal vs polyclonal antibodies: which to buy, and what drives the cost

Polyclonal antibodies are collected from the serum of an animal, commonly a rabbit or goat, immunised with the target protein or a peptide from it. Many B cells respond, so the serum contains a mixture of antibodies against different epitopes. The best preparations are antigen-affinity purified to remove antibodies that do not bind the target.

Monoclonal antibodies come from a single B-cell clone, classically fused into a hybridoma cell line, so every molecule is identical and binds one epitope. Recombinant monoclonals go a step further: the antibody’s genes are sequenced and expressed in cell culture, so the same antibody can be made again indefinitely.

• Western blot: both work well. Polyclonals often give a stronger signal; monoclonals give cleaner single bands.
• IHC on fixed tissue: polyclonals tolerate formalin fixation well; well-validated monoclonals give the most consistent staining across a long study. Either may need antigen retrieval first.
• Immunoprecipitation: polyclonals often capture native proteins efficiently because they bind several sites.
• Sandwich ELISA: a monoclonal capture antibody paired with a polyclonal or second monoclonal detection antibody is common. See the guide to ELISA types.
• Flow cytometry and diagnostics-style assays: monoclonals, for their specificity and reproducibility.

Whatever the application, the deciding question is whether the antibody has been validated for it. The applications guide explains why validation does not transfer between methods.

1. Immunogen: the full protein, a fragment or a peptide, and which region it covers.
2. Host species: it decides which secondary antibody you need.
3. Species reactivity: confirmed for the species of your samples.
4. Validated applications, with images, dilutions and the samples used.
5. Purification: antigen-affinity purified is the most specific polyclonal format.
6. Concentration and buffer: note glycerol and preservatives such as sodium azide.
7. Storage and lot: how to store it, and whether the lot you receive matches the validation data.

Antibody prices vary widely, and the vial price alone says little. The main drivers are:

• Production method: polyclonal serum is cheapest to make, hybridoma monoclonals cost more, recombinant monoclonals more again.
• Purification: affinity purification against the antigen adds cost and specificity.
• Validation depth: testing in several applications, cell lines and knockout controls costs money and saves yours.
• Conjugation: HRP, biotin or fluorophore labels add a manufacturing step.
• Pack size and concentration: a smaller vial at a higher concentration can be the cheaper option.

Buy from a supplier who shares the full datasheet with validation images before you order, tells you the lot you will receive, and ships cold. Our antibody range covers more than 11,000 monoclonal, polyclonal, secondary, labelled and control antibodies validated by western blot, IHC and immunofluorescence. Send the target, species and application and we send matching options with their datasheets.