The effect of lysine deprivation on leukemic blood.

Studies have shown that specific amino acids are required for optimal growth of leukemic versus normal cells, and it is believed that the depletion of selected amino acids can abrogate tumor growth. We have developed a technique for studying the effect of amino acid deprivation on leukemic cell proliferation. The technique is based on the controlled enzymatic removal of the amino acid from leukemic blood and the subsequent measurement of cell proliferative capacity. The specific system being studied is the removal of lysine from blood using immobilized L-lysineα-oxidase.A reactor has been designed that consists of L-lysineα-oxidase and catalase co-immobilized within the void space of the porous region of asymmetric hollow fiber (ultrafiltration) membranes. Blood from leukemic sheep is currently being treatedin vitro with this reactor. By varying treatment time, the amount of enzyme immobilized, and the blood flow rate, the amount of lysine removed from the blood can be varied and controlled. Preliminary data indicate that 80% depletion of lysine from leukemic blood is enough to cause a significant (25%) decrease in total white cell count as well as a decrease in the proliferative capacity of the leukemic cells.