Because their expression patterns overlap only partly, the pair provides a comparative profile rather than a single identity call. CD31 highlights endothelial-associated cells but can also appear on some blood cells, while CD45 marks hematopoietic cells. Examining both signals therefore helps distinguish endothelial, hematopoietic, and intermediate or transitional populations more effectively.
During embryonic blood development, researchers can compare cells according to their combined CD31 and CD45 signals to follow populations associated with vascular and hematopoietic states. This is especially useful for examining the endothelial-to-hematopoietic transition, where transitional populations are of interest. The profile helps organize candidate populations for lineage analysis without relying on either marker in isolation.
CD31 is enriched on endothelial cells, but it is also present on some blood cells. Consequently, CD31-positive cells cannot automatically be assigned an endothelial identity. Adding CD45 supplies complementary information about hematopoietic association, reducing ambiguity when researchers analyze developing vascular and blood populations during embryonic development.
Researchers label cells with fluorescent antibodies against CD31 and CD45, then examine the resulting signals by flow cytometry or microscopy. The two-marker pattern is used to characterize endothelial, hematopoietic, or transitional populations. Depending on the experimental design, identified populations can support cell isolation or subsequent lineage-analysis studies in developmental samples.
By assigning cells to marker-defined populations, the analysis supports questions about which cells are associated with endothelial or hematopoietic compartments and which may occupy a transitional category. Those assignments can guide cell isolation and lineage analysis, helping investigators connect marker patterns with the development of vascular and blood systems.
The approach is suited to studies that connect vascular development with blood formation. In embryonic samples, researchers can use the marker combination to characterize populations, examine the endothelial-to-hematopoietic transition, and select cells for lineage analysis. These applications make the pair useful for investigating how endothelial and hematopoietic systems emerge and relate to one another.