title: Constitutive expression of IL-7 receptor alpha does not support increased expansion or prevent contraction of antigen-specific CD4 or CD8 T cells following Listeria monocytogenes infection.
abstract: Expression of IL-7Ralpha (CD127) has been suggested as a major determinant in the survival of memory T cell precursors. We investigated whether constitutive expression of IL-7Ralpha on T cells increased expansion and/or decreased contraction of endogenous Ag-specific CD4 and CD8 T cells following infection with Listeria monocytogenes. The results indicate that constitutive expression of IL-7Ralpha alone was not enough to impart an expansion or survival advantage to CD8 T cells responding to infection, and did not increase memory CD8 T cell numbers over those observed in wild-type controls. Constitutive expression of IL-7Ralpha did allow for slightly prolonged expansion of Ag-specific CD4 T cells; however, it did not alter the contraction phase or protect against the waning of memory T cell numbers at later times after infection. Memory CD4 and CD8 T cells generated in IL-7Ralpha transgenic mice expanded similarly to wild-type T cells after secondary infection, and immunized IL-7Ralpha transgenic mice were fully protected against lethal bacterial challenge demonstrating that constitutive expression of IL-7Ralpha does not impair, or markedly improve memory/secondary effector T cell function. These results indicate that expression of IL-7Ralpha alone does not support increased survival of effector Ag-specific CD4 or CD8 T cells into the memory phase following bacterial infection.
authors.affiliation: Department of Microbiology, Carver School of Medicine, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Jodie S
authors.initials: JS
authors.lastname: Haring
authors.forename: Xuefang
authors.initials: X
authors.lastname: Jing
authors.forename: Julie
authors.initials: J
authors.lastname: Bollenbacher-Reilley
authors.forename: Hai-Hui
authors.initials: HH
authors.lastname: Xue
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Leonard
authors.forename: John T
authors.initials: JT
authors.lastname: Harty
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D016923:Cell Death / Q000235:genetics / Q000276:immunology; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000276:immunology*; D006131:Growth Inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D007156:Immunologic Memory / Q000235:genetics; D008089:Listeria monocytogenes / Q000276:immunology; D008088:Listeriosis / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008213:Lymphocyte Activation / Q000235:genetics; D018655:Lymphocyte Count; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020395:Receptors, Interleukin-7 / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology
chemical_list: D018984:Epitopes, T-Lymphocyte; D006131:Growth Inhibitors; D020395:Receptors, Interleukin-7; C415350:interleukin-7 receptor, alpha chain