Regulation of RAG-1 and CD69 expression in the thymus during positive and negative selection

Eur J Immunol. 1994 Jan;24(1):145-51. doi: 10.1002/eji.1830240122.


Successful interaction of the T cell receptor (TCR) with major histocompatibility complex (MHC) molecules during thymic selection down-regulates the expression of the recombination activating genes (RAG)-1 and -2 in cortical thymocytes and thereby prevents further endogenous TCR alpha-chain gene rearrangements (Borgulya, P., Kishi, H., Uematsu, Y. and von Boehmer, H., Cell. 1992. 69: 529-537; Brändle, D., Müller, C., Rülicke, T., Hengartner, H. and Pircher, H., Proc. Natl. Acad. Sci. USA 1992. 89: 9529-9533). To address the question whether down-regulation of RAG-1 activity represents an irreversible process we have blocked TCR-MHC interactions of thymocytes with thymic stromal cells. Firstly, transgenic (Tg) mice expressing a virus-specific MHC class I (H-2Db)-restricted TCR were injected with anti-Db or anti-CD8 monoclonal antibodies and RAG-1 expression was examined by in situ hybridization on thymus sections. The results show that cortical thymocytes up-regulated RAG-1 expression within 24 h after antibody administration. Secondly, immature thymocytes from TCR Tg mice were released from the thymic microenvironment and cultured in vitro for 14 h in single-cell suspension. The amount of RAG-1 mRNA was increased sixfold in cultured cells when compared to freshly isolated thymocytes. In addition, we show that immature thymocytes from TCR transgenic mice bearing non-selective MHC molecules (H-2d) down-regulated RAG-1 expression after antigen-induced TCR engagement. Cytofluorometric analysis further revealed that surface expression of CD69 on immature thymocytes inversely correlated with RAG-1 expression during positive and negative selection processes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Antigens, CD / biosynthesis*
  • Antigens, Differentiation, T-Lymphocyte / biosynthesis*
  • Blotting, Northern
  • Cell Differentiation / physiology
  • Flow Cytometry
  • H-2 Antigens
  • Homeodomain Proteins*
  • In Situ Hybridization
  • Lectins, C-Type
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Protein Biosynthesis*
  • Receptors, Antigen, T-Cell, alpha-beta
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes / physiology
  • Thymus Gland / cytology*
  • Thymus Gland / metabolism*


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation, T-Lymphocyte
  • CD69 antigen
  • H-2 Antigens
  • Homeodomain Proteins
  • Lectins, C-Type
  • Receptors, Antigen, T-Cell, alpha-beta
  • RAG-1 protein