Activity of neutral endopeptidase and aminopeptidase N in mouse thymic stromal cells which bind double-positive thymocytes

Myra Small*, Meirav Kaiser, William Tse, Shelly Heimfeld, Shmaryahu Blumberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The activity of two peptidases was determined in immortalized lines of thymic stromal cells. A line of total stromal cells (T-TG-St) was grown from transgenic mouse expressing temperature-sensitive SV40 T antigen under the control of the regulatory elements of the mouse major histocompatibility complex class I gene. From these cells we isolated a subset (DP-TG-St) that binds thymocytes which are mainly CD4+8+. We also assayed a clone of fetal thymic epithelial cells (BA/10) that binds CD4+8+ thymocytes. Both lines of double-positive cell-binding stroma exhibited strong activity of two peptidases, neutral endopeptidase (NEP; EC 3.4.24.11) and aminopeptidase N (APN; EC 3.4.11.2). In contrast, the activity of both enzymes was very low in the total thymic stromal line. Use of specific inhibitors confirmed that these two enzymes were responsible for the activity observed but also suggested the presence of additional unidentified aminopeptidase(s) in the same stromal cells. The high activity of the two peptidases on stromal cells that bind thymocytes at the double-positive stage raises the possibility that they might contribute to the microenvironment of the developing thymocytes.

Original languageEnglish (US)
Pages (from-to)961-964
Number of pages4
JournalEuropean Journal of Immunology
Volume26
Issue number4
DOIs
StatePublished - Apr 1 1996

Keywords

  • Aminopeptidase N
  • Double-positive thymocyte-binding stroma
  • Neutral endopeptidase

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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