Interaction of the synthetic immunomodulatory dipeptide bestim with murine macrophages and thymocytes

• Published in: Russian journal of bioorganic chemistry Vol. 34; no. 1; pp. 37 - 42
• Main Authors: Kolobov, A. A, Kolodkin, N. I, Zolotarev, Yu. A, Tuthill, C, Navolotskaya, E. V
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : SP MAIK Nauka/Interperiodica 2008; SP MAIK Nauka/Interperiodica
• Subjects: adenylate cyclase; Biochemistry; Biomedical and Life Sciences; Biomedicine; Bioorganic Chemistry; immune system; Life Sciences; Organic Chemistry; peptides; receptors; immune system; peptides; receptors; adenylate cyclase
• ISSN: 1068-1620; 1608-330X; 1573-9163
• DOI: 10.1134/S1068162008010044

The tritium-labeled dipeptide bestim (γ-D-Glu-L-Trp) with a specific activity of 45 Ci/mmol was obtained by high-temperature solid-state catalytic isotope exchange. It was found that [³H]bestim binds with a high affinity to murine peritoneal macrophages (K d 2.1 ± 0.1 nM) and thymocytes (K d 3.1 ± 0.2 nM), as well as with plasma membranes isolated from these cells (K d 18.6 ± 0.2 and 16.7 ± 0.3 nM, respectively). The specific binding of [³H]bestim to macrophages and thymocytes was inhibited by the unlabeled dipeptide thymogen (L-Glu-L-Trp) (K i 0.9 ± 0.1 and 1.1 ± 0.1 nM, respectively). After treatment with trypsin, macrophages and thymocytes lost the ability to bind [³H]bestim. Bestim in the concentration range of 10⁻¹⁰ to 10⁻⁶ M reduced the adenylate cyclase activity in the membranes of murine macrophages and thymocytes.