The MIH43 monoclonal antibody specifically binds to human B7-H4 (B7 family member, H4) that is encoded by the VTCN1 (V-set domain containing T cell activation inhibitor 1) gene. B7-H4 is a type I membrane glycoprotein with a calculated molecular weight of 30.89 kDa. It is also known as VCTN1, B7h.5, B7S1 (B7 superfamily member 1) or B7X. B7-H4 is a newly discovered member of the B7 family of costimulatory proteins. B7-H4 is not constitutively expressed on peripheral tissues. Its expression can be induced on macrophages, dendritic cells, B cells and T cells. By binding to its putative receptor, the function of B7-H4 was initially reported to be a negative regulator of T cell activation, proliferation and differentiation related to cytokine production and cytotoxic effector cell functions. B7-H4 is reportedly overexpressed in a variety tumors. B7-H4 expression by tumor macrophages appears to play a role in suppression antigen-specific T cell mediated immunity. Recent studies indicate that B7-H4 can also be a positive regulator of T cell responses. B7-H4 can be involved innate immunity as well, eg, by inhibiting neutrophil expansion.
The antibody was conjugated to an oligonucleotide that contains an antibody clone-specific barcode (ABC) flanked by a poly-A tail on the 3' end and a PCR handle (PCR primer binding site) on the 5' end. The ABC for this antibody was designed to be used with other BD AbSeq oligonucleotides conjugated to other antibodies. All AbSeq ABC sequences were selected in silico to be unique from human and mouse genomes, have low predicted secondary structure, and have high Hamming distance within the BD AbSeq portfolio, to allow for sequencing error correction and unique mapping. The poly-A tail of the oligonucleotide allows the ABC to be captured by the BD Rhapsody™ system or other oligo-dT-based capture systems. The 5' PCR handle allows for efficient sequencing library generation for Illumina sequencing platforms.