Calf thymosin was injected subcutaneously in daily doses of 0.1 to 3 mg for 12 to 15 days into adult thymectomized, irradiated bone marrow reconstituted (THXB) mice. Thymosin partially restored the ability of the T-cell depleted host to develop delayed type hypersensitivity to sheep erythrocytes. The degree of restoration varied from 50 t0 75% of control values. Thymosin treatment of normal mice potentiated the footpad responsiveness to sheep erythrocytes by as much as 50% over that of untreated controls. The optimum dosage of thymosin seemed to be in the 200 to 500 μg range, and multiple injections were essential for a significant response. Twelve daily injections of 100 to 500 μg of thymosin restored T cell reactivity to the THXB mouse, but the responsiveness decayed relatively rapidly once the treatment was stopped. The restoration of immune responsiveness to sheep erythrocytes in T-cell depleted mice provides a convenient means of demonstrating activity in thymosin preparations in vivo.
ASJC Scopus subject areas
- Infectious Diseases