T-cell proliferation in vivo and the role of cytokines.
Unlike typical naive T cells, T cells with an activated (CD44hi) memory phenotype show a rapid rate of proliferation in vivo. The turnover of memory-phenotype CD8+ T cells can be considerably augmented by injecting mice with various compounds, including polyinosinic polycytidylic acid, lipopolysaccharide and immunostimulatory DNA (CpG DNA). Certain cytokines, notably type I (alpha, beta) interferons (IFN-I), have a similar effect. These agents appear to induce proliferation of CD44hi CD8+ cells in vivo by an indirect process involving production of effector cytokines, possibly interleukin-15, by antigen-presenting cells. Although none of the agents tested induces proliferation of naive-phenotype T cells, IFN-I has the capacity to cause upregulation of surface markers on purified naive T cells. Depending upon the experimental conditions used, IFN-I can either inhibit or enhance primary responses of naive T cells to specific antigen.
Sprent
J
J
Department of Immunology, IMM4, The Scripps Research Institute, La Jolla, CA 92037, USA. jsprent@scripps.edu
Zhang
X
X
Sun
S
S
Tough
D
D
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002455:Cell Division; D002470:Cell Survival; D016207:Cytokines / Q000276:immunology*; D018960:Hyaluronan Receptors / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology; D007370:Interferon Type I / Q000276:immunology; D019409:Interleukin-15 / Q000276:immunology; D051379:Mice; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D016207:Cytokines; D018960:Hyaluronan Receptors; D007370:Interferon Type I; D019409:Interleukin-15