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A cytotoxic proteinase isolated from human lymphocytes
Journal of Immunology (Baltimore, Md. : 1950)
|February 1, 1978
Summary
Human lymphocytes contain a cytotoxic proteinase that can kill cancer cells. This enzyme, distinct from trypsin, may play a role in immune responses and warrants further investigation for therapeutic potential.
Area of Science:
- Immunology
- Biochemistry
- Cell Biology
Background:
- Unstimulated human peripheral blood lymphocytes possess cytotoxic potential.
- The specific enzymes mediating this cytotoxicity are not fully characterized.
Purpose of the Study:
- To isolate and characterize a cytotoxic proteinase from human lymphocytes.
- To investigate the role of this proteinase in cell-mediated cytotoxicity.
Main Methods:
- Gel filtration and affinity chromatography were used for protein isolation.
- Enzyme activity was assessed using cytotoxicity assays with labeled carcinoma cells.
- Inhibition studies were performed using diisopropylfluorophosphate (DFP) and soybean trypsin inhibitor (STI).
Main Results:
- A proteinase of approximately 30,000 daltons was isolated.
- The enzyme exhibited significant cytotoxicity against T24 human bladder carcinoma cells.
- Cytotoxicity was observed at lower concentrations compared to trypsin and confirmed with a 51Cr release assay.
Conclusions:
- Unstimulated human lymphocytes harbor a cytotoxic proteinase.
- This lymphocyte-derived proteinase demonstrates specific cytotoxic activity against tumor cells.
- The identified proteinase is a potential mediator of lymphocyte-mediated cytotoxicity.