CD 69 expression during selection and maturation of CD4+8+ thymocytes

Wojciech Swat, Mark Dessing, Harald Von Boehmer, Pawel Kisielow

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253 Scopus citations


We have analyzed the inducibility of protein kinase C (PKC)‐dependent expression of CD 69 molecules in T cell receptor (TCR) transgenic thymocytes developing in the presence or absence of selecting, class I major histocompatibility complex (MHC) molecules. Small CD4+8+ thymocytes developing in the absence of selecting MHC molecules could not be induced to express CD 69 by TCR cross‐linking even after spontaneous in vitro up‐regulation of their TCR level which resulted in enhanced Ca++ flux. In contrast, a small proportion of CD4+8+TCRlow and most TCRhigh (CD4+8+ and CD4+8+) thymocytes developing in the presence of selecting MHC ligands could be induced to express CD 69 upon TCR cross‐linking. Unlike the anti‐TCR antibody, phorbol 12‐myristate 13‐acetate ‐ a direct activator of PKC ‐ induced the expression of CD 69 on all thymocytes. These results suggest that positive selection of CD4+8+ thymocytes results in coupling of TCR‐mediated signals to the CD 69 expression pathway. In vitro analysis of thymocytes before and after positive selection suggests that (1) positive selection does not immediately result in resistance to deletion and (2) that sustained TCR ligation is needed to promote maturation of positively selected CD4+8+ thymocytes resulting in gradual loss of the sensitivity to deletion and acquisition of the ability to proliferate in response to TCR‐mediated signals.

Original languageEnglish
Pages (from-to)739-746
Number of pages8
JournalEuropean Journal of Immunology
Issue number3
StatePublished - Mar 1993
Externally publishedYes


  • CD48 thymocytes
  • CD69
  • Deletion
  • Positive selection
  • T cell receptor signaling


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