The 1-155-2 monoclonal antibody specifically recognizes human immunoglobulin lambda light chains (Igλ). Immunoglobulins are expressed on the surface of B lymphocytes and plasma cells, and they also circulate in the serum. The two light chains in an immunoglobulin are of the same type, either kappa (Igκ) or Igλ. Immunoglobulins bearing Igλ are expressed on a minority of normal B lymphocytes and on neoplastic cells of some leukemias, lymphomas, and plasmacytomas. In serum, the 1-155-2 antibody binds to immunoglobulins bearing Igλ as well as free Igλ. It does not bind to Igκ or immunoglobulin heavy chains.
The antibody was conjugated to BD Horizon™ BV650 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 650-nm. BD Horizon BV650 can be excited by the violet laser and detected in a filter used to detect APC-like dyes (eg, 660/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there will be spillover into the APC and Alexa Fluor® 700 detectors. However, the spillover can be corrected through compensation as with any other dye combination.