CD276
Description
The CD276 (CD276 molecule) is a protein-coding gene located on chromosome 15.
CD276, also known as B7-H3, is a human protein encoded by the CD276 gene. It is a type I transmembrane protein with two isoforms, determined by its extracellular domain. In mice, the extracellular domain consists of a single pair of immunoglobulin variable (IgV)-like and immunoglobulin constant (IgC)-like domains. However, in humans, it can have one pair (2Ig-B7-H3) or two identical pairs (4Ig-B7-H3) due to exon duplication. While B7-H3 mRNA is expressed in most normal tissues, its protein expression is limited due to post-transcriptional regulation by microRNAs. However, B7-H3 protein is highly expressed on many cancer types (60% of all cancers). The 4Ig-B7-H3 isoform is predominant in cancer. B7-H3 plays an inhibitory role in adaptive immunity in non-malignant tissues, suppressing T cell activation and proliferation. In malignant tissues, it acts as an immune checkpoint molecule inhibiting tumor antigen-specific immune responses. B7-H3 also exhibits non-immunological pro-tumorigenic functions, including promoting migration, invasion, angiogenesis, chemoresistance, epithelial-to-mesenchymal transition, and affecting tumor cell metabolism.
CD276 may play a role in regulating T-cell mediated immune responses. It may protect tumor cells by inhibiting natural killer cell lysis and act as a marker for neuroblastoma cells. CD276 may be involved in acute and chronic transplant rejection and in regulating lymphocytic activity in mucosal surfaces. Additionally, it may play a crucial role in providing the placenta and fetus with an appropriate immune environment during pregnancy. Both isoforms 1 and 2 appear to be redundant in their ability to modulate CD4 T-cell responses. However, isoform 2 has been shown to enhance the induction of cytotoxic T-cells and selectively stimulate interferon gamma production in the presence of T-cell receptor signaling.
CD276 is also known as 4Ig-B7-H3, B7-H3, B7H3, B7RP-2.
