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

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.