The TRAP1 monoclonal antibody specifically binds to CD154. CD154 is a 39 kDa type II membrane glycoprotein that is a member of the tumor necrosis factor superfamily, Tumor necrosis factor ligand superfamily member 5 (TNFSF5). CD154 is expressed on a variety of cell types including activated CD4+ T cells and some CD8+ T cells, NK cells, mast cells and basophils. CD154 is also known as CD40 ligand (CD40L); it serves as a ligand for CD40 that is expressed on B cells, macrophages, and dendritic cells. The expression of CD154 by activated T-helper cells costimulates B-cell activation and proliferation through binding to CD40 expressed on B cells. In response to T-dependent antigens, the CD154 and CD40 interaction is required for B-lymphocyte differentiation, including immunoglobulin production and isotype switching and memory B cell generation. The TRAP1 antibody can partially block T cell-B cell interaction and inhibit the subsequent proliferation, differentiation, and memory formation of B cells. It has been reported that patients with X-linked hyper-IgM syndrome have defective expression of functional CD154 due to mutations in the CD40LG gene that encodes CD154.
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.