The 4E5 monoclonal antibody specifically recognizes Ly-49D, which is expressed on subsets of natural killer (NK) cells in C57BL/6, C3H/He (at a very low frequency), and SJL, but not DBA/2, AKR, CBA/J, or BALB/c mice. Unlike Ly-49D antigen has not been betected on NK-1.1+ (or DX5+) T cells. In 129/J mice, the 4E5 antibody cross-reacts with Ly-49O, Ly-49R, and Ly-49V. The Ly-49 family of NK-cell receptors, members of the C-type lectin superfamily, are disulfide-linked type-II transmembrane protein homodimers with extracellular carbohydrate-recognition domains, which bind to MHC class I alloantigens. The Ly-49 family members are expressed independently, such that an individual NK or T cell may display more than one class of Ly-49 receptor homodimers. Ly-49D weakly binds to MHC class I antigens of the k halpotype, and Ly-49D+ IL-2-activated NK cells lyse target cells expressing H-2[a], H-2[b], H-2[d], H-2[k], H-2[p], H-2[q], and H-2[s] and the CHO (Chinese hamster ovary) cell line. Ly-49D+ cells mediate allogenic resistance to H-2d bone marrow transplantation. In vitro studies suggest that the Ly-49D receptor mediates activation of NK-cell cytolytic activity via tyrosine phosphorylation of their ITIMs (Immunoreceptor Tyrosine-based Inhibitory Motifs). Molecular differences between the Ly-49D stimulatory receptor and the inhibitory members of the Ly-49 family include the absence of an ITIM in Ly-49D, the lack of phosphorylation of Ly-49D in activated NK cells, and the association of a novel tyrosine-phosphorylated protein (pp16) with Ly-49D in activated NK cells. Ly-49O and Ly-49V are closely related to Ly-49A[B6] and, like Ly-49A, have ITIM domains. Ly-49O- and Ly-49V-transfected 293T (human kidney epithelial) cells bind tetramers of H-2D[b], D[b], D[k], and L[d]. In addition, the Ly-49V-transfected cells also bind K[b], K[d], and K[k]. Ly-49R is closely related to Ly-49D[B6] and is putative activating receptor due to its lack of an ITIM domain. Ly-49R-transfected 293T cells bind soluble tetramers of H-2D[b], D[d], D[k], and L[d].
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.