L-asparagine requirements of human T-lymphocytes and B-lymphocytes in culture

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 coli L-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.