Abstract: Process and apparatus for the continuous purification and concentration of leukocytes from blood, characterized in that said process comprises the following steps: (a) seperating plasma from the blood by filtration in order to achieve a filtered buffy coat fraction; (b) adding an aqueous solution, which is hypotonic in relation to plasma, to the buffy coat fraction from step (a), in order to achieve lysation of erythrocytes contained in the buffy coat fraction; (c) mixing the buffy coat fraction and the aqueous hypotonic solution from step (b) in a mixing device; (d) leading the mixture from step (c) through a retention vessel; (e) leading the mixture from step (d) through a centrifuge in order to seperate the leukocytes; (f) collecting the separated leukocytes from step (e).

Abstract: A nutrient medium for protein producing cells, characterized in that said medium consists essentially of the following components: a physiological saline containing Ca2+, K+, Mg2+ and Na+, an energy source, a pH buffer and methionine in an amount of 0.015-2.0 g/liter, and optionally antibiotics. The invention further relates to use of the nutrient medium for cells and human leukocytes.