title: Restoration of CD28 expression in CD28- CD8+ memory effector T cells reconstitutes antigen-induced IL-2 production.
abstract: The control of many persistent viral infections by Ag-specific cytolytic CD8+ T cells requires a concurrent virus-specific CD4+ Th cell response. This reflects in part a requirement of activated effector CD8+ T cells for paracrine IL-2 production as a growth and survival factor. In human CMV and HIV infection, the majority of differentiated virus-specific CD8+ T cells notably lose the ability to produce IL-2 but also lose expression of CD28, a costimulatory molecule. Analysis of the fraction of memory CD8+ T cells that continue to express CD28 revealed these cells retain the ability to produce IL-2. Therefore, we examined if IL-2 production by CD28- CD8+ T cells could be restored by introduction of a constitutively expressed CD28 gene. Expression of CD28 in CD28- CD8+ CMV- and HIV-specific CD8+ T cells reconstituted the ability to produce IL-2, which could sustain an autocrine proliferative response after Ag recognition. These results suggest that the loss of CD28 expression during differentiation of memory/effector CD8+ T cells represents a decisive step in establishing regulation of responding CD8+ T cells, increasing the dependence on CD4+ Th for proliferation after target recognition, and has implications for the treatment of viral disease with adoptively transferred CD8+ T cells.
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors.forename: Max S
authors.initials: MS
authors.lastname: Topp
authors.forename: Stanley R
authors.initials: SR
authors.lastname: Riddell
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Akatsuka
authors.forename: Michael C
authors.initials: MC
authors.lastname: Jensen
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Blattman
authors.forename: Philip D
authors.initials: PD
authors.lastname: Greenberg
mesh_terms: D018106:CD28 Antigens / Q000378:metabolism*; D003587:Cytomegalovirus / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D015497:HIV-1 / Q000276:immunology; D015234:HLA-A Antigens / Q000378:metabolism; D015789:HLA-A2 Antigen; D006801:Humans; D007156:Immunologic Memory; D007376:Interleukin-2 / Q000378:metabolism*; D008213:Lymphocyte Activation; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism*
chemical_list: D018106:CD28 Antigens; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D007376:Interleukin-2