A specific serine proteinase is inducible in Lyt-2+,L3T4- and Lyt-2-,L3T4+ T cells in vitro but is mainly associated with Lyt-2+,L3T4- effector cells in vivo

Eur J Immunol. 1986 Dec;16(12):1559-68. doi: 10.1002/eji.1830161215.


Recently, we and others reported on the expression of a serine proteinase in long-term cultured murine T lymphocyte cell lines. In an attempt to explore the distribution and possible regulation of this enzyme in T lymphocyte subsets, we performed the presented detailed study. We found that the proteinase is not expressed by thymocytes and resting T cells but can be induced by lectin or antigen in combination with lymphokine sources in vitro in macrophage-depleted unselected T cells as well as in both T cell subsets (Lyt-2+,L3T4- and Lyt-2-,L3T4+) separated by flow cytofluorometry. Furthermore, it appears that cell-associated proteinase activity is increasing with prolonged culture period of sensitized T lymphocytes and that it is higher in antigen-activated as compared to lectin-activated T cells. When tested for substrate specificity the T cell-associated proteinase was shown to preferentially cleave model peptide substrates carrying L-arginine at position P1 in combination with nonpolar amino acids at position P2 and P3. As concluded from its sensitivity to proteinase inhibitors the enzyme can be classified as a serine proteinase and by molecular sieving at high ionic strength it was shown to have a mol. mass of approximately 50-60 kDa. Analysis of in vivo activated T cells revealed that this particular proteinase was expressed in flow cytofluorometry sorted lymphocytic choriomeningitis virus-specific Lyt-2+,L3T4- cytolytic T lymphocytes but not in Lyt-2-,L3T4+ T cells presensitized with either Listeria monocytogenes or I-A alloantigens. The data demonstrate that the two T cell subsets (Lyt-2+,L3T4-; Lyt-2-,L3T4+) have distinct in vitro induction requirements for the expression of proteinase and that after activation of T cells in vivo the enzyme is preferentially associated with Lyt-2+,L3T4- effector cells.

MeSH terms

  • Animals
  • Antigens, Differentiation, T-Lymphocyte
  • Antigens, Surface / analysis*
  • Chromatography, Gel
  • Clone Cells
  • Cytotoxicity, Immunologic
  • Endopeptidases / analysis
  • Endopeptidases / biosynthesis*
  • Enzyme Induction
  • Flow Cytometry
  • Isoflurophate / metabolism
  • Lectins / pharmacology
  • Lymphocyte Activation
  • Lymphokines / pharmacology
  • Mice
  • Mice, Inbred C57BL
  • Protease Inhibitors
  • Serine Endopeptidases
  • Substrate Specificity
  • T-Lymphocytes / classification
  • T-Lymphocytes / enzymology*


  • Antigens, Differentiation, T-Lymphocyte
  • Antigens, Surface
  • Lectins
  • Lymphokines
  • Protease Inhibitors
  • Isoflurophate
  • Endopeptidases
  • Serine Endopeptidases