The 3D3 monoclonal antibody specifically recognizes FcγRII (CD32), a 40 kDa, polymorphic type I transmembrane glycoprotein that serves as a low affinity receptor for aggregated IgG. This highly glycosylated molecule (encoded by at least two different genes) is expressed on monocytes, granulocytes, platelets and B cells. Unlike the FLI28.26 mAb, the 3D3 mAb detected a polymorphic CD32 antigen expressed on B cells of all donors, but only on platelets, monocytes and granulocytes of some donors. The platelets from 3D3+ donors respond to certain stimulatory mAb such as CD165 (clone SN2) which results in aggregation. On the other hand, the platelets from 3D3 negative donors do not form aggregates after stimulation. Individuals can be divided into two groups as responder and non-responder depending on expression, or non-expression, of 3D3. In comparison to the 3D3 mAb, the FLI8.26 mAb detects a monomorphic CD32 antigen expressed on all human donors.
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. The 5' PCR handle allows for efficient sequencing library generation for Illumina sequencing platforms.
NOTE: The BD Rhapsody Single-Cell Analysis System must be used with the BD Rhapsody Express Instrument.