Mitogenic proteinases from human leukocytes.

Serine proteinase activity has been identified in purified human lymphocyte membranes, and the corresponding enzymes have been isolated from human leukocyte extracts by affinity chromatography. The localization of these enzymes on lymphocyte and granulocyte membranes has been immunochemically demonstrated. Mitogenic activity towards human lymphocytes has been demonstrated for these enzymes, and anti proteinase antibodies inhibit the growth of transformed lymphocytes. The proteinases are similar in many properties to enzymes previously isolated from human leukocytes, and reported to be involved in a wide variety of leukocyte functions.