Biotinylated B7-H3 (4Ig)/B7-H3b His&Avi Tag Protein, Human

B7-H3 (CD276) is an immune checkpoint molecule whose protein structure in humans primarily features tandemly repeated Ig-like V-C domains (VC domains) due to gene duplication, whereas mice contain only a single VC domain. This protein participates in regulating T-cell-mediated immune responses, with both isoform 1 and isoform 2 capable of modulating CD4+ T-cell reactions, among which isoform 2 enhances the induction of cytotoxic T cells and selectively stimulates IFN-γ production in the presence of TCR signaling. In tumors, B7-H3 exerts a protective effect by inhibiting natural killer (NK) cell-mediated lysis, and also serves as a detection marker for neuroblastoma. Furthermore, it plays a role in acute and chronic transplant rejection as well as in the regulation of lymphocytic activity at mucosal surfaces, and contributes to establishing a suitable immunological environment for the placenta and fetus during pregnancy. Its clinical significance lies in its potential as a therapeutic target for tumor immunotherapy and transplant rejection intervention, as well as its research value in pregnancy-related immune regulation.