Synthesis and biological activity of eight thymulin analogues.
Eight analogues of thymulin, a thymic nonapeptide involved in several aspects of T-cell differentiation, were synthesized by the conventional method in solution. Four were modified in residue 7 (Ala, D-Ala, D-Leu or Sar instead of Gly) and two in residue 8 (D-Ser or Thr instead of Ser); in the others, the Gly6-Gly7 sequence was replaced either by a single glycyl residue or by a triglycyl sequence. The biological activity of the analogues was determined in the rosette assay: five exhibited a prolonged activity in vivo with respect to thymulin. All the analogues inhibited the binding of tritiated thymulin to thymulin receptors on three human lymphoblastoid T-cell lines (HSB2, 1301 and CEM) with the same order of magnitude as non-labelled thymulin.
D000596:Amino Acids / Q000032:analysis; D006801:Humans; D011971:Receptors, Immunologic / Q000032:analysis; D012397:Rosette Formation; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000276:immunology; D013935:Thymic Factor, Circulating / Q000032:analysis / Q000138:chemical synthesis / Q000276:immunology*; D013951:Thymus Hormones / Q000276:immunology*
D000596:Amino Acids; D011971:Receptors, Immunologic; D013951:Thymus Hormones; C033482:serum thymic factor receptor; D013935:Thymic Factor, Circulating