The pre-B cell receptor (pre-BCR) expressed during the early stages of B lymphocyte development is a heterodimer of immunoglobulin heavy chain (IgH) with surrogate light chain, which is an Ig-light-chain-like molecule composed of the non-covalently linked Lambda 5 (λ5) and VpreB proteins. The pre-BCR is believed to control IgH repertoire selection and proliferation of differentiating B lymphocytes. The SL156 antibody reacts with a conformational epitope of the pre-BCR in transfected X63-Ag8.653 cells but not with surrogate light chain, λ5, or VpreB in the absence of IgH. It detects pre-BCR on pre-B cell lines, but not on pro-B cell lines or IgM-positive splenocytes. It also detects pre-BCR on the surface of pre-B cells, but not on Ig light chain (IgL)-positive B lymphocytes, from the bone marrow of normal mice. It has been noted that the cell-surface expression of pre-BCR is upregulated after a one-hour incubation of bone-marrow leukocytes in tissue culture medium at 37°C. After immunization, cell-surface pre-BCR is detected on a subset of splenic IgL+ germinal-center B lymphocytes.
This antibody is conjugated to BD Horizon™ BV605 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max of 602-nm, BD Horizon BV605 can be excited by a violet laser and detected with a standard 610/20-nm filter set. BD Horizon BV605 is a tandem fluorochrome of BD Horizon BV421 and an acceptor dye with an Em max at 605-nm. Due to the excitation of the acceptor dye by the green (532 nm) and yellow-green (561 nm) lasers, there will be significant spillover into the PE and BD Horizon PE-CF594 detectors off the green or yellow-green lasers. BD Horizon BV605 conjugates are very bright, often exhibiting brightness equivalent to PE conjugates and can be used as a third color off of the violet laser.