Recombinant Mouse BTNL3 Fc Chimera Protein, CF

Butyrophilin-like 3 (BTNL3), also referred to as BTNL1, Gm316, and Ng10, is a member of the BTN/MOG Ig-superfamily and shares structural resemblance to the B7 family (1). BTNL3 is a type I transmembrane protein that consists of an extracellular domain (ECD) containing two IgV domains, a single transmembrane domain, and a cytoplasmic domain with a B30.2/SPRY region. Mature mouse BTNL3 shares 30% and 80% amino acid sequence identity with human and rat BTNL3, respectively. BTNL3 mRNA has been identified in many tissues including small intestine, colon, liver, lung, bone marrow and spleen tissue, and it is highly expressed in neutrophils (2-6). The specific function of BTNL3 has yet to be fully elucidated, but BTNL3 is suggested to be a novel negative regulator for T cell activation and immune diseases (7). In humans, BTNL3 has been shown to form heterodimers with BTNL8 and overexpression of this complex leads to CD69 upregulation and T cell antigen receptor downregulation (8). In mice, BTNL3 can form heterodimers with BTNL6 and modulate local immune responses and intraepithelial lymphocytes–epithelial cell interaction pathways (9). Additionally, BTNL3 has been shown to bind directly to V gamma 4+ T cell receptor, suggesting a role in gamma delta T cell regulation (10). BTNL3 expression has also been found to be down-regulated in colon cancer tumors (11). R&D Systems in house data indicate that mouse BTNL3 protein inhibits the secretion of IL-2 from anti-CD3 activated mouse CD3+ T cells.