Used in immunological research to study T-cell activation and co-stimulatory signaling pathways. Supports the development of therapeutic antibodies and immune checkpoint modulators by serving as a binding target for drug candidates. Employed in ELISA, surface plasmon resonance, and other assay systems to measure antibody affinity and specificity. Facilitates cross-reactivity studies due to high homology with human CD27. The His tag enables easy purification and detection in recombinant protein applications.