The 4A5 monoclonal antibody binds to the glycosylated type I membrane protein ROR1 (Receptor-tyrosine-kinase-like Orphan Receptor 1). The ROR1 and ROR2 related proteins are highly conserved evolutionarily and are primarily expressed during embryogenesis. ROR1 is not expressed on normal peripheral blood lymphocytes. ROR1 is similar to tropomyosin receptor kinase (Trk family) neurotropic receptors and shares a cysteine-rich domain with Frizzled receptors for Wnt-family signaling proteins, which are involved in the regulation of embryogenesis and carcinogenesis. Furthermore, there is mounting evidence that aberrant ROR1 expression contributes to human malignancy.
The antibody was conjugated to BD Horizon Red 718, which has been developed exclusively for BD Biosciences as a better alternative to Alexa Fluor® 700. BD Horizon Red 718 can be excited by the red laser (628 – 640 nm) and, with an Em Max around 718 nm, it can be detected using a 730/45 nm filter. Due to similar excitation and emission properties, we do not recommend using R718 in combination with APC-R700 or Alexa Fluor® 700.