Syntheses of thymopoietins and their immunological effects: Relationship of amino acid sequence to immunological activity

Abstract

Peptides and fragment analogs of the thymopoietin (TP) family have been synthesized using conventional synthesis in solution and tested for immunological effects on the impaired lymphocytes of uremic patients. These studies indicate that the Arg-residue of the sequence 32 to 36 of thymopoietin II is necessary for restoring activity of E-rosette formation on reduced E-rosette formation in uremic patients and the shortest peptide fragment of thymopoietin II (thymopentin), Arg-Lys-Asp-Val-Tyr, increased the activity of E-rosette-forming cells similarly to the longer chain of thymopoietin fragments containing thymopentin in their sequences. The synthetic human thymopoietin (hTP) showed restorative effect on the impaired T-lymphocyte activity of uremic patients as well as the synthetic two other synthetic thymopoietins, bovine thymopoietin I (bTP-I) and bovine thymopoietin II (bTP-II). However, the restoring activity of the synthetic bovine thymopoietin III (bTP-III or bovine splenin) was lower than that of the synthetic bTP-I. A synthetic analog of human splenin (hSP), [Glu34]hSP showed an enhancing effect on the reduced B-lymphocytes of uremic patients.