Cross Reactive Antibodies for Flow Cytometry

Flow cytometry panel design is a critical step in developing a flow cytometry protocol, but this can be a time consuming process, especially if you are working with a panel using four colors or more. Commercially available fluorescently-labeled antibodies are often species-specific, but some antibodies recognize highly conserved target epitopes and can be used to label cells from different species. Incorporating these cross-reactive antibodies into a flow cytometry panel can save you time as you work up panels for different species, be they mice, non-human primates (NHP), or humans. Consider these factors when looking for or using a cross-reactive antibody.

1. With what different species are you working?

Working with similar species, such as mouse and rat, or NHP and human, usually opens up more options of cross reactive antibodies, as there are generally greater levels of homology between targets of interest, such as CD4 or MHC class I, between closely related species.

2. How are you searching for cross-reactive antibodies?

Many commercial providers of flow cytometry-ready antibodies have species reactivity information or search portals on their websites that indicate species specificity. Using this information, you can discern quickly which targets may be cross-reactive.

3. Always do pilot experiments.

No matter what the research literature or commercial documents say about an antibody, you must always assess its cross reactivity with your own laboratory samples and equipment. Both time and money can be saved to rule out antibodies with suboptimal staining performance. Pilot experiments with samples from multiple species is also critical to assessing overall compatibility with different staining panels.

4. Do your long term goals include GLP (good laboratory practices)-compliant assays or clinical trials?

Determine if your cross-reactive antibody would be in regulatory compliance, if you are doing preliminary research in animal models with plans of developing a GLP-compliant assay for use in preclinical assessments or clinical trials. These cross-reactive antibodies may be well suited for use in NHP and human samples, which would make them suitable for clinical use, as long as regulatory compliance can be satisfied.