Restoration by serum thymic factor of colony‐forming unit (CFU‐S) entry into DNA synthesis in thymectomized mice after T‐dependent antigen treatment

Abstract
Adult thymectomy prevents stimulation of hematopoietic stem cells as measured by colony-forming units (CFU-S) if T-dependent antigens are injected, but not when T- independent antigens are used. This can be observed as soon as 10 to 15 days after thymectomy. The serum thymic factor can restore CFU-S response to T-dependent antigens in thymectomized mice.