Commercially-available kits are an effective way to streamline animal research. Containing all the necessary components to achieve reproducible, high-quality data, these products are supplied with user-friendly protocols for straightforward incorporation into existing workflows. By using rigorously tested, pre-optimised kits, researchers can save significant amounts of time that might otherwise be focussed on assay development and troubleshooting.
Kits for animal research include enzyme-linked immunosorbent assay (ELISA), lateral flow assay (LFA), and quantitative PCR (qPCR). These are often compatible with a wide range of sample materials, including serum, urine, milk, saliva, tissue homogenates and cell lysates. The highly sensitive nature of these products allows for samples to be heavily diluted before use, which is important to conserve limited material.
Easy to perform and delivering quantitative data for even low-abundance targets, ELISA is widely-used to monitor a diversity of analytes with relevance to animal research. The choice of ELISA format is typically dictated by the nature of the target biomolecule, with sandwich ELISA regularly chosen to analyse complex samples, and competitive ELISA often more suitable to detect very small analytes.
Lateral flow assays are used routinely to diagnose various infections that are commonly found in animals, delivering results within minutes via a clear, visual indicator. During a typical lateral flow assay, a small quantity of material is applied to the sample well, from which it migrates along the test strip. Here, antibodies are immobilised as a test band and a control band. The presence of the analyte of interest generates a visible test band to confirm the presence of infection, while the control band is used to indicate a valid result.
qPCR has wide-ranging utility in animal research. Using a fluorescent reporter molecule to monitor the progress of DNA amplification, it delivers real-time, quantitative analysis of gene expression. Depending on the choice of primers, qPCR may afford detection of the presence of an infectious agent; allow monitoring of a biomarker to diagnose disease; or deliver comparative data between different members of the same species, such as multiple individuals within an in vivo study group.
Antibodies are essential reagents to support a wide range of research techniques. These include mainstream methods such as Western blotting, immunocytochemistry, immunohistochemistry (IHC), ELISA and immunoprecipitation (IP), as well as techniques such as LFA, immuno-PCR and a variety of in vivo studies. By binding target antigens with exceptional specificity and affinity, antibodies allow accurate detection of even low-abundance analytes.
Since many target antigens share a high degree of sequence homology, antibodies often have the capacity to detect different species variants of the same protein. For this reason, many antibody reagents have utility across both human and animal research. To ensure that an antibody is suitable for its intended purpose, it is sensible to study the accompanying datasheet to ascertain which applications the antibody is suitable for and which species it is reactive to. Where the antibody has not been evaluated against a certain species, a sequence alignment between the immunising antigen and the target protein within the species of interest can provide an indication of likely reactivity.
Antibodies for animal research may be primary or secondary; monoclonal or polyclonal; recombinant or generated by immunisation; unconjugated; or bound to a detection moiety such as an enzyme or fluorescent dye. The choice of antibody will be driven by the downstream assay format and the nature of the research, meaning it is important to consider multiple properties of the antibody during selection.
In vivo-grade antibodies have considerable utility within animal research, where they are often used within animal models to study the effects of neutralization, blocking and activation/proliferation, or to image specific cells or tissues. To avoid adverse effects, these products are of high purity; free of endotoxin, pathogens, preservative, stabilizer, and carrier protein; and show little tendency to aggregate. Many in vivo-grade antibodies are recombinant, since recombinant technology can be used to engineer desirable features such as an extended serum half-life.
Proteins have many utilities within animal research. They can be employed as functional biomolecules to support cell growth, as antigens during antibody production, as positive controls within various assays, or as reagents to facilitate detection. Proteins are also used as essential blocking agents in techniques such as immunocytochemistry or IHC, where they function to minimise background staining by preventing non-specific antibody binding.
The selection of a native or recombinant protein, a peptide, or a tagged molecule will be largely driven by the type of research which is to be performed. Native proteins typically share a high degree of similarity with the in vivo biomolecule, making them a popular choice for functional assays or as diagnostic markers. Recombinant proteins may be engineered to express a specific mutation, allowing the study of a known disease state, or might be modified in some way to improve solubility or bioactivity. Peptides are frequently used as immunogens or as controls in techniques such as ELISA, while tagged proteins are widely exploited for detection.
Since human and animal proteins can exhibit key differences, it is often necessary to use animal proteins for animal research. Although a considerably greater range of human proteins may be commercially-available, it is important to acknowledge that a protein derived from the species of interest may be required to produce meaningful results in an animal study.