抄録
Medullasin, a serine protease found in bone marrow cells, resembles pancreatic elastase but has no elastinolytic activity. The protease exists in both erythroblasts and granulocytes. Medullasin in granulocytes plays an important role in biophylaxis. The protease activity in granulocytes elevated in patients with chronic inflammation in active phase, and decreased to normal levels in remission. Injection of a small amount of medullasin into the skin caused inflammation characterized by the infiltration of a large number of macrophages. Therefore, the protease in granulocytes is speculated to play an important role in the development of inflammation. Treatment of human lymphocytes with a small amount of medullasin caused an increment of both RNA and DNA synthesis of them, and also mitogens' effect on human lymphocytes was potentiated by medullasin treatment. Medullasin enhanced human natural killer cell activity by inducing the maturation of natural killer cells from immature large granular lymphocytes. The effect of medullasin was not mediated through the production of interferons or interleukin-2. Chemotactic activity of monocytes was inhibited, and superoxiside production of them stimulated by medullasin treatment. The protease also enhanced the cytotoxic activity of monocytes. From these results described above, medullasin in granulocytes is considered to play an important role in biophylaxis.
