Synthesis of a new biological response modifier thyrnosin β(4) analogue and its restorative effect on depressed

Thymosin β(4) 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 β(4), [Phe(4F)(12)] deacetyl- thymosin β(4), 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 β(4) 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 β(4).