The synthetic peptide related to the central part of human interleukin-2 molecule accelerates growth and vascularization of sarcoma 180 in mice

The synthetic peptide C-1-6 related to the central part of human interleuki n 2 molecule (sequence 59-72; N- and C-modified) had been shown previously to inhibit cytotoxic activity of macrophages converting them to synthesis o f growth factors. In this paper the effect of C-1-6 on growth of sarcoma 18 0 in mice was studied. C-1-6 significantly accelerated tumor growth having been injected into mice in dose 5 or 50 mu g per animal since the 4(th) day after tumor cells transplantation. Supernatants of Mphi in vitro activated by C-1-6 (10 mu g/ml) and injected into mice also accelerated significantl y sarcoma mass diurnal increasing as compared to mice treated with supernat ants of non-activated Mphi or activated with bacterial lipopolysaccharide. A single injection of C-1-6 into mice either at the day or at the next day of tumor cells inoculation increased significantly the number of vessels gr owing up to transplant, thus the forming of the vascular bed had preceded t umor volume enlargement.