Recovery of T-cell functions in aged mice injected with synthetic thymosin-α1

Injection of immunodeficient, aged mice with synthetic thymosin-α1, a 28 amino acid residues peptide, before carrier priming enhances helper activity. Helper activity was titrated in vitro by adding graded numbers of HRBC-primed spleen cells from aging mice to cultures containing a constant number of spleen cells from 3-month-old normal mice and TNP-HRBC. The in vitro anti-TNP response is enhanced if the aging mice are injected with microgram quantities of α1 before carrier priming. As suggested by the shape of the titration curves α1 appears to increase T cell-T cell cooperation involved in the generation of helper cell activity. The in vitro proliferative response of lymph node cells from OVA-primed aging mice is also restored by injection of α1. Thus, T-cell functions which are markedly reduced in senescence can be efficiently repaired by injection of synthetic thymosin-α1.