The R139 monoclonal antibody specifically binds to CD93 which is also known as Complement component C1q receptor (C1qR), C1q receptor 1 (C1qR1), or Matrix-remodeling-associated protein 4 (MXRA4). The immunogen used to generate the R139 hybridoma was a preparation of CD93 protein. Human CD93 is a transmembrane glycoprotein that is highly expressed on monocytes, macrophages, granulocytes, and endothelial cells but not on T and B lymphocytes. CD93 is also known as the C1q/MBL/SPA Receptor as it binds C1q, the recognition subunit of the first component (C1) of the complement pathway, as well as MBL (Mannose-binding-lectin) and SPA (Pulmonary Surfactant Protein A). Human C1qRp is involved in the C1q-mediated enhancement of phagocytosis. R139 is suitable to detect CD93 expression on cells of myeloid lineage by flow cytometry, and CD93 in cellular lysates by Western blotting or immunoprecipitation. In addition, R139 reportedly neutralizes C1q-mediated enhancement of phagocytosis. CD93 has also been reported to define a human stem cell population with hematopoietic and hepatic potential.
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.