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 cytotoxicity 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.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1978|
ASJC Scopus subject areas
- Immunology and Allergy