B7-H7/HHLA2 Full-Length and Domain-Specific ECD Proteins

B7-H7, encoded by HHLA2, is a type I transmembrane member of the B7 family of immune-regulatory proteins. Its extracellular region contains multiple immunoglobulin-like domains, giving HHLA2 a distinctive architecture within the B7 family. HHLA2 is expressed in humans and selected primates but lacks a direct murine ortholog, creating unique considerations for translational and antibody-development studies. HHLA2 interacts with immune receptors including TMIGD2/CD28H and can modulate T-cell and other immune-cell responses in a context-dependent manner. Elevated HHLA2 expression has been reported in multiple solid tumors and is associated with the tumor immune microenvironment, making it an emerging immune-checkpoint target.

Currently, DIMA BIOTECH provides several recombinant B7-H7 proteins, including the full extracellular domain together with proteins covering residues 23–137, 132–234, and 223–344. These domain-specific proteins can be used for ELISA, immunization, antibody screening, epitope mapping, domain-recognition studies, and comparative binding analysis. Because different HHLA2 extracellular regions may contribute differently to receptor interactions and immune-regulatory activity, combining full ECD with multiple fragments provides a useful strategy for identifying antibodies against specific functional epitopes.