Growth Factors & Cytokines

B- and T-lymphocyte attenuator (BTLA), or CD272, is a type I transmembrane co-inhibitory receptor of the CD28 receptor family that is involved in modulating adaptive immune responses and T cell co-stimulation. BTLA acts in a manner similar to PD-1 and CTLA-4, the other inhibitory receptors of the CD28 family, as an anti-inflammatory molecule crucial to dampening immune response. Expressed most prominently in T cells, including Th1, Th2, CD4+, and CD8+ cells, BTLA can also be found in B cells, NK cells, dendritic cells and macrophages. Ligation of BTLA with HVEM, a member of the TNF receptor super family (TNFRSF), induces tyrosine phosphorylation of ITIM and ITSM motifs found within the BTLA cytoplasmic domain, resulting in association with SHP-1 and SHP-2. While HVEM’s interactions with the ligands LIGHT and Lymphotoxin-α induce a powerful stimulatory immune response, the interaction of BTLA and HVEM attenuates T cell proliferation and the production of cytokines including IL-2, IL-10 and IFN-γ. This interaction between BTLA and HVEM is the only receptor-ligand interaction known to bridge the CD28 and TNFR families. Recent studies provide evidence that engagement of BTLA’s third cytoplasmic motif, Grb2, may transmit a positive signal, suggesting both a co-inhibitory and co-stimulatory role for BTLA. Dysfunction of the BTLA pathway plays a role in the pathogenesis of numerous autoimmune diseases and cancers. The naturally occurring human BTLA monomer consists of a 127-amino-acid extracellular domain, a 21-amino-acid transmembrane domain, and a 111-amino-acid cytoplasmic domain. PeproTech’s CHO cell-derived Recombinant Human BTLA Fc is a glycosylated, disulfide-linked homodimer of 353-amino-acid-residues whose monomer consists of a 120-amino-acid portion of the extracellular domain fused to the 231-amino-acid length Fc portion of human IgG by two glycine residues. The calculated molecular weight of monomeric CHO cell-derived Recombinant Human BTLA Fc is 39.8 kDa; however, due to glycosylation, it migrates at an apparent molecular weight of approximately 50-55 kDa by SDS-PAGE analysis under reducing conditions.