title: Reconstitution of T cell functions in aging mice by thymosin alpha 1.
abstract: Helper T cell activity of spleen cells from BDF1 mice is impaired by aging but is restored to a large extent by injection of thymosin alpha 1, a synthetic peptide consisting of 28 amino acid residues. Injection of an equimolar amount of the N14 (N-terminal half of thymosin alpha 1) synthetic fragment is at least as effective as the entire alpha 1 molecule in increasing helper T cell activity of spleen cells from old (6-18 months) mice but not from young (3 months) mice. Conversely, injection of the C14 (C-terminal half of thymosin alpha 1) synthetic fragment is devoid of any effect in both young and old mice. Since helper T cell activity of spleen cells from old mice is also increased by injection of interleukin-2, the observed enhancement of interleukin-2 production by mitogen-activated spleen cells from old mice upon injection of thymosin alpha 1 or the N14 fragment suggests that these peptides amplify helper T cell activity by increasing the cell precursor frequency of interleukin-2-producing T cells. This conclusion is further supported by the finding that injection of thymosin alpha 1, or its N14, but not C14, fragment enhances the expression of interleukin-2 receptors on mitogen-activated spleen cells from old but not from young mice.
mesh_terms: D000375:Aging; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004912:Erythrocytes / Q000276:immunology; D006736:Horses; D007111:Immunity, Cellular / Q000187:drug effects*; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011863:Radioimmunoassay; D012756:Sheep; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000276:immunology; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D007376:Interleukin-2; D013947:Thymosin; D000077596:Thymalfasin