Synthesis of a new biological response modifier thyrnosin β₄ analogue and its restorative effect on depressed

Abstract

Thymosin β₄ is a polypeptide isolated from thymosin fraction 5. This peptide exhibits important activities in the regulation and differentiation of thymus-dependent lymphocytes. An analogue of thymosin β₄, [Phe(4F)¹²] deacetyl- thymosin β₄, was synthesized by a solution method, followed by deprotection with 1 M trifluoromethanesulphonic acid (TFMSA)-thioanisole (molar ratio, 1:1) in trifluoroacetic acid (TFA) in the presence of dimethlselenium. Finally, the deprotected peptide was incubated with dithiothreitol to reduce sulphoxide on the methionine side chain. The synthetic [Phe(4F)¹²]deacetyl-thymosin β₄ was found to have a restoring effect on the impaired blastogenic response of T-lymphocytes isolated from uraemic patients with recurrent infectious diseases. This analogue exhibited stronger restorative activity than that of our synthetic deacetyl-thymosin β₄.