title: Thymocyte-thymocyte interaction for efficient positive selection and maturation of CD4 T cells.
abstract: Despite numerous reports on MHC class II expression by T cells from a wide spectrum of mammalian species including humans, the biological relevance of this phenomenon has never been tested with appropriately designed animal models. To address this issue, we developed mouse models in which immature thymocytes are the only positively selecting antigen-presenting cells in the thymus. In these mice, CD4+ T cells were generated with the appropriate maturation phenotype and showed a diverse repertoire of TCR Vbetas. The CD4+ T cells were functionally competent, mediating effective allogeneic responses that involved polyclonal TCR Vbetas. These results suggest that the thymocyte-thymocyte (T-T) interaction operates as an independent pathway for CD4+ T cell selection in the thymi of species with MHC II-positive thymocytes. This T-T interaction appears to be the basis for the generation of donor MHC-restricted CD4+ T cells in xenogeneic hosts.
authors.affiliation: Graduate Program of Immunology, Seoul National University College of Medicine, Seoul 110-799, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Kyeong Cheon
authors.initials: KC
authors.lastname: Jung
authors.forename: Hyo Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Doo Hyun
authors.initials: DH
authors.lastname: Chung
authors.forename: Jin Sook
authors.initials: JS
authors.lastname: Song
authors.forename: Seung Don
authors.initials: SD
authors.lastname: Yang
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Simpson
authors.forename: Seong Hoe
authors.initials: SH
authors.lastname: Park
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology*; D002454:Cell Differentiation; D006801:Humans; D016130:Immunophenotyping; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators