Lymphocyte Separation Medium
LSM is a sterile, iso-osmotic polysucrose and diatrizoate solution with low viscosity originally designed for the in vitro isolation of lymphocytes from diluted whole blood. Principle of Procedure Lymphocyte Separation Medium (LSM) is based on the adapted method of isolating lymphocytes using centrifugation techniques by BØyum in which diluted defibrinated blood is layered on a solution of Sodium Metrizoate and Dextran or Ficoll® and centrifuged at low speeds for 30 minutes. Differential migration following centrifugation will result in the formation of several cell layers. Mononuclear cells (lymphocytes and monocytes) and platelets will be contained in the banded plasma - LSM interphase due to their density. The pellet that is formed contains mostly erythrocytes and granulocytes, which have migrated through the gradient to the bottom of the tube. Lymphocytes are recovered by aspirating the plasma layer and then removing the cells. Excess platelets, LSM, and plasma can then be removed by cell washing. Reagents Mediatech's Lymphocyte Separation Medium (Catalog No. 25-072-**) is a sterile filtered solution containing 106.91 g/L of Diatrizoic Acid and 68.181 g/L Polysucrose400 at a density of 1.077-1.080 g/mL @ 20ºC. The solution has an osmolarity of 290 + 20 mOsm and a pH of 7.0 + 2.0. Sodium Hydroxide is added as needed to adjust pH.