Influence of myelopeptide-2 on tumor growth and interaction between tumor cells and lymphocytes in vitro

Effects of different doses of myelopeptide-2 (MP-2) (0.1; 1 and 50 mug/ml) on tumor cell growth and interaction between tumor cells and lymphocytes in vitro were studied. Tumor cells and lymphocytes from distant and regional lymph nodes of C57BL/6 mice bearing B16 melanoma as well as tumor cells and autologic peripheral blood lymphocytes of patients with malignant melanoma have been investigated. The most pronounced inhibition of the growth of B1 6 melanoma and human malignant melanoma cells was evident at MP-2 dose of 5 0 mug/ml. The same dose of MP-2 was also shown to increase the inhibition o f B16 melanoma cell growth caused by regional and distant lymph node lympho cytes of mice. MP-2 doses 0.1 and 1 mug/ml increased antitumor activity of regional lymph node lymphocytes, while the dose 1 mug/ml increased also ant itumor activity of distant lymph node lymphocytes of mice bearing B16 melan oma. However, at the same doses no increase of inhibitory effect of human d onor and intact mice lymphocytes was detected. MP-2 at all the doses under study (0.1; 1 and 50 mug/ml) increased inhibitory effect of peripheral bloo d lymphocytes from patients with melanoma towards autologic malignant melan oma cells.