B7-H3, also known as CD276, is a type I transmembrane glycoprotein and member of the B7-CD28 immune checkpoint protein family with roles in the T cell-mediated immune response.1,2 It is encoded by CD276 in humans and is composed of an N-terminal signal peptide, an extracellular domain containing two identical pairs of immunoglobulin (Ig) constant (IgC) and variable (IgV) domains, a transmembrane region, and an intracellular tail. CD276 is ubiquitously expressed, however, protein expression is post-transcriptionally regulated.2 B7-H3 protein is constitutively expressed on non-immune fibroblasts, endothelial cells, and osteoblasts, and can be induced in immune cells such as dendritic cells, macrophages, natural killer (NK) cells, and T cells. It inhibits NK cell-mediated lysis, as well as induces co-inhibition of T cells, increases activation of tumor-specific cytotoxic T cells, and decreases proliferation of CD4+ and CD8+ T cells through modulation of nuclear factor of activated T cells (NFAT), NF-κB, and AP-1. Serum levels of B7-H3 are increased in patients with sepsis, as are intestinal levels in patients with graft versus host disease. High tumor levels of B7-H3 protein are associated with increased tumor size, poorly differentiated tumors, lymph invasion, and shorter overall survival in patients with lung and breast cancers.3 Cayman's B7-H3/CD276 (C-Term) Rabbit Monoclonal Antibody (Clone RM335) can be used for immunohistochemistry (IHC) and Western blot (WB) applications.WARNING This product is not for human or veterinary use.
