Cyclolinopeptide derivatives modify methotrexate-induced suppression of the humoral immune response in mice
摘要:
High doses of chemotherapeutics in clinical treatment, leading to cell toxicity, can be lowered by co-administration of other immunoregulatory drugs. The aim of this study was to evaluate effects of several derivatives of cyclolinopeptide A (CLA), derived from linen seeds, on the suppressive action of metothrexate (MTX) in a mouse model of humoral immune response in vitro. New CIA analogues 1 and 2, and their linear precursors 3 and 4, containing conformationally restricted dipeptide fragment Phe-Phe or d-Phe-d-Phe with ethylene bridge (-CH2-CH2-) between phenylalanine nitrogens were synthesized. NMR studies and theoretical calculations showed that introduction of locally constraining fragment into CLA molecule increased its overall conformational flexibility.The bioactivity of new CIA analogues was examined in the mouse model of the in vitro secondary humoral immune response, suppressed by methotrexate (MTX). The results revealed differential actions of the peptides such as 1/augmentation of the suppressive activity of MIX or 2/antagonistic effects of the peptides on MIX-induced suppression. Potential advantages for the application of CIA-derived peptides in therapy and structure activity relationships were discussed. (C) 2011 Elsevier Masson SAS. All rights reserved.