Human CD155 gene encodes a trans-membrane protein which mediates NK cell adhesion and triggers NK cell effector functions. It binds two different NK cell receptors: CD96 and CD226. These interactions accumulate at the cell-cell contact site, leading to the formation of a mature immunological synapse between NK cell and target cell. This may trigger adhesion and secretion of lytic granules and IFN-gamma and activate cytoxicity of activated NK cells. CD155 may also promote NK cell-target cell modular exchange, and PVR transfer to the NK cell. This transfer is more important in some tumor cells expressing a lot of PVR, and may trigger fratricide NK cell activation, providing tumors with a mechanism of immune-evasion. CD155 plays a role in mediating tumor cell invasion and migration. CD155 serves as a receptor for poliovirus attachment to target cells. It may play a role in axonal transport of poliovirus, by targeting virion-PVR-containing endocytic vesicles to the microtubular network through interaction with DYNLT1. This interaction would drive the virus-containing vesicle to the axonal retrograde transport. CD155 can form trans-heterodimers with PVRL3/nectin-3. The extracellular domain interacts with VTN, CD226 and CD96. The cytoplasmic domain interacts with DYNLT1. Interacts with HHV-5 UL141. Interacts with poliovirus capsid composed of VP1, VP2 and VP3, mainly through VP3. It also binds with high affinity to TIGIT.

Full-length extracellular domain of human CD155 cDNA (21 – 343aa, derived from BC015542) was constructed with codon optimization gene synthesis and expressed with a human alpha Fetal Protein N-terminal (AFPn) -His-TEV cleavage site Tag (217aa) fusion at its N-terminall. This protein was expressed in E. coli as inclusion bodies. The final product was refolded using our unique “temperature shift inclusion body refolding” technology and chromatographically purified.

1. May be used for in vitro CD155 mediated NK activation regulation study with this protein either as soluble factor or as coating matrix protein.

2. May be used for protein-protein interaction assay.

3. Potential Therapeutic, which may be used as NK activities regulator for immune-modulating in vivo (recombinant CD155 protein or anti-CD155 antibody) for various diseases.