The T47-530 specifically recognizes the Lymphocyte Activation Gene 3 (LAG-3) protein which is also known as, Protein FDC, or CD223. LAG-3 is a ~70 kDa type I transmembrane glycoprotein that belongs to the Ig superfamily and exhibits homology to CD4. LAG-3 is expressed on NK cells, regulatory T cells, and activated conventional T cells with higher expression found on CD8+ T cells compared with CD4+ T cells. LAG-3 is an activation induced cell surface molecule that like CD4, binds MHC class II molecules, but with much higher affinity. This may enable LAG-3 to act as a negative competitor of CD4 for MHC class II ligand binding. LAG-3 may associate with the TCR-CD3 complex to downregulate TCR signal transduction and T cell clonal expansion. In contrast, LAG-3-induced signaling may promote dendritic cell activation.
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.