BTNL3 ELISA Kits

Phylogenetically, ubiquitously expressed type I glycoprotein butyrophilin (BTN) molecules share a common ancestor with other members of the B7-CD28 superfamily. In humans, BTN genes are located in the telomeric part close to HLA class I region of the chromosome 6p. BTN molecules are divided in three subfamilies (BTN1, BTN2, and BTN3). The BTN3A (CD277) subfamily, then contains three isoforms BTN3A1, -A2, and -A3, belonging to the immunoglobulin (Ig) superfamily and sharing a high structural homology for the extracellular domain composed of an Ig-like IgV and an IgC domain. While the ectodomain of the three BTN3A isoforms have a very high homology (>95%), only BTN3A1 and BTN3A3 isoforms express an intracellular portion which is composed of a poorly conserved PRY/SPRY B30.2.

A study investigated CD277-containing butyrophilin 3A1 (BTN3A1), a poorly investigated immunoregulatory pathway driven by myeloid and tumor cells in ovarian tumor beds. It showed that BTN3A1 is overexpressed in ovarian cancer and is associated with a significant survival disadvantage in these patients. Concomitantly, ectopic expression of BTN3A1 on APCs inhibits __ T cell proliferation and Th1 cytokine production. Proteomic analyses and binding assays demonstrate that BTN3A1 interacts with the CD45 phosphatase and elements of the TCR. Consequently, TCR ligation in the presence of BTN3A1 inhibits the segregation of CD45 from the immune synapse and blunts downstream signaling by antagonizing the phosphorylation of CD3Zeta, Lck, and Zap70. Overall, the study shows that BTN3A1 drives __ T cell dysfunction in ovarian cancer, while _CD277 antibodies transform this molecule from immunosuppressive to immunostimulatory by rescuing __ T cells and activating __ T cells, thus dynamically unleashing T cell-driven antitumor immunity.