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

Markus M. Simon*, Ulli Fruth, Hans Georg Simon, Michael D. Kramer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


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+, L3T4and Lyt‐2, L3T4+) separated by flow cyto‐fluorometry. 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 ∼ 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+, L3T4effector cells.

Original languageEnglish (US)
Pages (from-to)1559-1568
Number of pages10
JournalEuropean Journal of Immunology
Issue number12
StatePublished - 1986

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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