The In-1 monoclonal antibody specifically binds to CD74, the MHC class II-associated Invariant chain (Ii), expressed in I-A+ cell populations. Although it is predominantly expressed intracellularly, it has also been detected on the cell surface of some B-cell lines and at low levels on a small number of B lymphocytes. In the mouse, alternatively spliced transcripts encode 31-kDa and 41-kDa isoforms, and the cell-surface CD74 has a chondroitin sulfate side chain which allows it to interact with CD44. CD74 is directly involved in the intracellular transport of MHC class II molecules and antigen presentation, and it affects the maturation of T and B lymphocytes.
The antibody was conjugated to BD Horizon™ BV480 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 436-nm and Em Max at 478-nm, BD Horizon BV480 can be excited by the violet laser and detected in the BD Horizon BV510 (525/40-nm) filter set. BV480 has less spillover into the BV605 detector and, in general, is brighter than BV510.