L-asparaginase-induced immunosuppression: effects on antibody-forming cells and serum titers.

Treatment of mice with L-asparaginase from Escherichia coli resulted in a marked suppression of the immune response, as assessed both cellularly and humorally. Suppression occurred only when the enzyme was injected together with the sheep erythrocytes used as antigen. There was little or no effect when the enzyme was injected before the antigen. Simultaneous injection of asparagine prevented suppression, an indication that the effect of the enzyme was due to depletion of an amino acid probably essential for normal lymphoid cell function during antibody production.