Suppression of Skin Hypersensitivity and Antibody Formation by L-Asparaginase

Abstract

Rabbits immunized with BSA in Freund's adjuvant were treated with different doses of L-asparaginase. The administration of this enzyme was started on the day of immunization and continued for 21 days. To measure the immunologic responses, weekly skin tests and quantitative antibody determinations were done. It was found that L-asparaginase in large doses (1000 IU/kg/day) suppressed both antibody formation and delayed hypersensitivity. With smaller doses, the suppression was partial and antibodies against L-asparaginase itself appeared in the serum, leading to a rapid elimination of the enzyme from the system by the end of the 3rd week. This rapid clearance of asparaginase in the latter part of its administration in small doses is probably due to the neutralizing effect of the antibodies, or rapid elimination of the antigen-antibody complexes, or a combination of the two. The possible mechanism and clinical significance of these findings was discussed.