Detection Method:Sandwich
Test principle:This assay employs a two-site sandwich ELISA to quantitate KIR2DS4 in samples. An antibody specific for KIR2DS4 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and anyKIR2DS4 present is bound by the immobilized antibody. After removing any unbound substances, a biotin-conjugated antibody specific for KIR2DS4 is added to the wells. After washing, Streptavidin conjugated Horseradish Peroxidase (HRP) is added to the wells. Following a wash to remove any unbound avidin-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of KIR2DS4 bound in the initial step. The color development is stopped and the intensity of the color is measured.
Product Overview:Using primers known to amplify HLA-C-specific NK receptors to screen clones with NK triggering activity, Bottino et al. (1996) also isolated a KIR2DS4 cDNA, which they termed KKA3. Sequence analysis revealed that KIR2DS4 encodes a deduced 304-amino acid protein with an extracellular domain similar to that of KIR2D p58 receptors; however, in the transmembrane region, there is a charged lysine residue, and the cytoplasmic tail has only 39 amino acids with no ITIM (immunoreceptor tyrosine-based inhibitory motif). KIRs with short cytoplasmic tails are associated with NK cell triggering rather than inhibition. Immunoprecipitation analysis showed that KIR2DS4 is expressed in 2 forms, one of 35 to 45 kD and the other of 55 to 58 kD. Flow cytometry analysis showed that KIR2DS4, unlike KIR2DS1 and KIR2DS2, was expressed in only a minority of individuals tested.
