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 CD179b (λ5) and CD179a (VpreB) proteins. The pre-BCR is believed to control IgH repertoire selection and proliferation of differentiating B lymphocytes. The LM34 antibody reacts with λ5 and surrogate light chain, but not VpreB alone, in transfected X63-Ag8.653 cells. It detects surrogate light chain on pro-B and pre-B cell lines, in the presence or absence of IgH, but not on IgM-positive B lymphocytes. It also detects surrogate light chain or λ5 on the surface and in the cytoplasm of pro-B or pre-B cells from the bone marrow of normal or RAG2-deficient mice. It has been noted that the (CD45R/B220) cell-surface expression of surrogate light chain is upregulated after a one-hour incubation of bone-marrow leukocytes in tissue culture medium at 37°C. At the earliest stages of B lymphopoiesis, before IgH is available, the surrogate light chain associates with a complex of glycoproteins, including a nonclassical cadherin, which could be involved in selective adhesion events during B-lymphocyte development. After immunization, cell-surface λ5 is detected on a subset of splenic Ig light chain-positive germinal-center B lymphocytes.
The antibody was conjugated to BD Horizon™ BV421 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max at 421-nm, BD Horizon BV421 can be excited by the violet laser and detected in the standard Pacific Blue™ filter set (eg, 450/50-nm filter). BD Horizon BV421 conjugates are very bright, often exhibiting a 10 fold improvement in brightness compared to Pacific Blue conjugates.