l-Asparagine Requirements of Human T-Lymphocytes and B-Lymphocytes in Culture

Abstract

The characterization of two human T-lymphocyte lines revealed that they required exogenous l-asparagine for cell growth, whereas all four B-cell lines studied were l-asparagine-independent. T-cells were 800–2,000 times more sensitive to Escherichia colil-asparaginase than were B-cells. The cytotoxic effects of a high concentration of l-asparaginase on B-cells were not related to the hydrolysis of l-asparagine but were due to heat-labile and heat-resistant substances in the enzyme. The findings were consistent with reports that l-asparaginase is effective in suppressing cellular immunity and inducing remission in patients with acute lymphocytic leukemia, mainly a non-B-cell disease. Thus these cell lines provide in vitro models for the study of a nutritional approach to chemotherapy or immunotherapy.