MHC class II-dependent T-T interactions create a diverse, functional and immunoregulatory reaction circle

You Jeong Lee, Kyeong Cheon Jung, Seong Hoe Park

Research output: Contribution to journalReview article

14 Scopus citations


Unlike conventional T cells, innate-like T cells such as natural killer (NK) T cells are selected by homotypic T-cell interactions. Recently, a few reports have shown that T-T CD4+ T cells can be generated in a similar manner to that for NKT cells. These two types of cells share common functional properties such as rapid response to antigenic encounters and the potential for a panoply of cytokine secretion. However, T-T CD4+ T cells differ from NKT cells in that they are restricted by highly polymorphic major histocompatibility complex (MHC) II molecules and have a diverse T-cell receptor repertoire. Additional example of T-T interactions was recently reported in which peripheral T cells re-circulate to the thymus and participate in the thymocyte selection process. In this review, we dissect the cellular mechanisms underlying the production of T-T CD4+ and NKT cells, with particular emphasis on the differences between these two T-cell prototypes. Finally, we propose that T-T CD4+ T cells serve two major functions: one as an acute-phase reactant against viral infection and the other is the generation of anti-ergotypic CD4+ T cells for regulatory purposes. All of these features make it possible to create a diverse set of functional cells through MHC class II-restricted T-T interactions.

Original languageEnglish
Pages (from-to)65-71
Number of pages7
JournalImmunology and Cell Biology
Issue number1
StatePublished - 16 Jan 2009


  • Non-conventional T cell
  • Re-circulation
  • T-T CD4 T cell
  • T-T interaction

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