Synthesis of calf thymosin beta 4 fragment 16-38 and its effect on the impaired blastogenic response of T-lymphocytes of a uremic patient with pneumonia

Functional roles of Phe of deacetyl-thymosin beta4 in the impaired blastogenic response of uraemic T-lymphocytes

Phe¹² of deacetyl-thymosin β₄ is one of the structural essentials for restorative effect on the impaired blastogenic response of uraemic T-lymphocytes. In order to evaluate the functional roles of this phenyl group in the restorative effect on impaired T-lymphocytes, two analogues, [1- Nal¹²]deacetyl-thymosin β₄ and [Cha¹²]deacetyl4 thymosin β₄, were synthesized by a solid-phase method and evaluated for restorative effect on the impaired blastogenic response of uraemic T-lymphocytes. The results indicated that [1-Nal¹²]deacetyl-thymosin β₄ which had a bulky naphthyl ring showed a stronger restorative effect than that of deacetyl-thymosin β₄, but it was slightly weaker than that of [Phe(4F)¹²]deacetyl-thymosin β₄. However, [Cha¹²]deacetyl-thymosin β₄ showed no restorative effect on the impaired blastogenic response of uraemic T-lymphocytes.

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

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.