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™ BB700, which is part of the BD Horizon Brilliant™ Blue family of dyes. It is a polymer-based tandem dye developed exclusively by BD Biosciences. With an excitation max of 485 nm and an emission max of 693 nm, BD Horizon BB700 can be excited by the 488 nm laser and detected in a standard PerCP-Cy™5.5 set (eg, 695/40-nm filter). This dye provides a much brighter alternative to PerCP-Cy5.5 with less cross laser excitation off the 405 nm and 355 nm lasers.