Antibodies for research
Research antibodies are immunoglobulins selected to bind a defined antigen and make it detectable in a laboratory method: western blot, ELISA, immunohistochemistry, immunofluorescence, immunoprecipitation, flow cytometry and ChIP. In the CABRU catalogue the category holds 21,314 references, made by FineTest, Cayman Chemical, ExBio, ReliaTech, BioVendor, Affinity Biologicals, G Biosciences and BioMedica Diagnostics.
What separates the sub-families
A primary antibody binds the antigen directly; a secondary binds the immunoglobulins of the species the primary was raised in and carries the label, enzymatic (HRP, alkaline phosphatase) or fluorescent. Among primaries, a monoclonal comes from a single clone and sees a single epitope: it gives contained background and consistent behaviour between lots, but loses signal when that epitope is altered by denaturation or fixation. A polyclonal is a mixture of specificities against different epitopes of the same antigen: it copes better with conformational changes and amplifies the signal on poorly expressed targets, at the cost of lot-to-lot variability to be re-checked at every reorder. The host species counts twice, because it must not match the sample species and it determines which secondary can be used.
How to choose between equivalent references
Validation does not transfer from one application to another. An antibody that works in western blot recognises a denatured epitope, and that alone does not make it usable in immunohistochemistry, where the same epitope is fixed and often masked. The catalogue application field lists the methods declared by the manufacturer and is the first filter to apply.
| Declared application | References in catalogue | What drives the choice |
|---|---|---|
| Western blot (WB) | 13,024 | Denatured epitope; working dilution and expected molecular weight matter |
| ELISA | 11,977 | A compatible capture/detection pair on distinct epitopes is required |
| Immunohistochemistry (IHC) | 8,083 | Paraffin sections (P) and frozen sections (F) behave differently |
| Flow cytometry (FC) | 5,377 | The fluorophore must match the cytometer laser and filter configuration |
| Immunofluorescence and ICC | 3,658 | Fixation and permeabilisation protocols are decisive |
Conjugates, pack sizes and storage
For flow cytometry the criterion is not only the target but the fluorophore: the ExBio range includes 1,336 unconjugated references and clones labelled with PE (1,166), APC (461), FITC (427), Alexa Fluor (280), PE-Cy tandems (214), PerCP (198), biotin (189) and Pacific Blue (132). On reactivity, 12,338 FineTest references declare a human target, 9,576 mouse and 6,690 rat, with rabbit as the prevailing host (9,864 references). Recurring pack sizes are 100 µg (12,001 references), 0.1 mg (1,315) and test-based packs for cytometry. Storage follows the datasheet: stated temperature, aliquoting on first opening to avoid repeated freeze-thaw cycles, fluorescent conjugates kept away from light.
What to check before ordering
Five fields decide whether a reference is the right one: antigen and clone, species reactivity, validated application, host and pack size. If the target is not listed a description is enough — gene or protein, species, method — and CABRU checks availability among the manufacturers it represents. The 21,314 references can be browsed in the product catalogue, filtering by company and application or searching by code and name.