title: Selective bystander proliferation of memory CD4+ and CD8+ T cells upon NK T or T cell activation.
abstract: Ag-experienced or memory T cells have increased reactivity to recall Ag, and can be distinguished from naive T cells by altered expression of surface markers such as CD44. Memory T cells have a high turnover rate, and CD8(+) memory T cells proliferate upon viral infection, in the presence of IFN-alphabeta and/or IL-15. In this study, we extend these findings by showing that activated NKT cells and superantigen-activated T cells induce extensive bystander proliferation of both CD8(+) and CD4(+) memory T cells. Moreover, proliferation of memory T cells can be induced by an IFN-alphabeta-independent, but IFN-gamma- or IL-12-dependent pathway. In these conditions of bystander activation, proliferating memory (CD44(high)) T cells do not derive from activation of naive (CD44(low)) T cells, but rather from bona fide memory CD44(high) T cells. Together, these data demonstrate that distinct pathways can induce bystander proliferation of memory T cells.
authors.affiliation: Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, Epalinges, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Eberl
authors.forename: P
authors.initials: P
authors.lastname: Brawand
authors.forename: H R
authors.initials: HR
authors.lastname: MacDonald
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D005699:Galactosylceramides / Q000494:pharmacology; D015236:HLA-C Antigens / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis; D007156:Immunologic Memory / Q000187:drug effects; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D012515:Mast-Cell Sarcoma; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018345:Mice, Knockout; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000637:transplantation
chemical_list: D018984:Epitopes, T-Lymphocyte; D005699:Galactosylceramides; D015236:HLA-C Antigens; C038653:HLA-C*03 antigen; D018960:Hyaluronan Receptors