The ACK45 monoclonal antibody specifically binds to CD117 (c-Kit), a transmembrane tyrosine-kinase receptor which is encoded by the Kit gene (formerly dominant white spotting, W). The c-Kit ligand (also known as steel factor, stem cell factor, and mast-cell growth factor) encoded by the Kitl gene (formerly steel, Sl), is a co-mitogen for hematopoietic stem cells and the myeloerythroid progenitors and a mast-cell differentiation factor. The Kit[W] and Kitl[Sl] mutant alleles have similar pleiotropic effects on the development of melanocytes, germ cells, and the hematopoietic system. In the adult bone marrow, CD117 is expressed on hematopoietic progenitor cells, including the CD90 (Thy-1)[lo] TER-119[-] CD45R/B220[-] CD11b (Mac-1)[-] Ly-6G (Gr-1)[-] CD4[-] CD8[-] Sca-1 (Ly-6A/E)[+] multipotent hematopoietic stem cells, progenitors committed to myeloid and/or erythroid lineages, and precursors of B and T lymphocytes. This widespread expression of CD117 in hematopoietic precursors is consistent with the participation of c-Kit and its ligand in the regulation of several hematopoietic lineages. Intrathymic expression of c-Kit and c-Kit ligand suggest that CD117 is also involved in the regulation of some events during the development of T lymphocytes. CD117 is also expressed by mast cells. The expression of CD117 has been included in protocols to isolate hematopoietic progenitors from fetal and adult peripheral blood. The specificity and functional activity of mAb ACK45 is very similar to that of the published antibody ACK22; it is reported to block the action of c-Kit in vitro and in vivo.
This antibody is routinely tested by flow cytometric analysis. Other applications were tested at BD Biosciences Pharmingen during antibody development only or reported in the literature.