A cytotoxic proteinase isolated from human lymphocytes.
A proteinase active at physiologic pH was isolated from unstimulated human peripheral blood lymphocytes with gel filtration and affinity chromatography. The proteinase with a molecular mass of approximately 30,000 daltons was completely inhibited by diisopropylfluorophosphate (DFP) and soybean trypsin inhibitor (STI). Incubation of the lymphocyte enzyme with 3H-proline labeled T24 human bladder carcinoma cells resulted in significant cytoxicity of the target cells. Cytotoxicity was only observed with much higher concentrations of trypsin. Similar results were obtained with a 51Cr release assay. This investigation demonstrates that unstimulated human peripheral blood lymphocytes contain a cytotoxic proteinase capable of killing pre-labeled target cells. The proteinase may be involved in lymphocyte-mediated cytotoxicity.
D003602:Cytotoxicity, Immunologic; D006801:Humans; D007531:Isoflurophate / Q000494:pharmacology; D008214:Lymphocytes / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D014360:Trypsin Inhibitor, Kunitz Soybean; D001749:Urinary Bladder Neoplasms / Q000378:metabolism
D007531:Isoflurophate; D014360:Trypsin Inhibitor, Kunitz Soybean; D010447:Peptide Hydrolases