title: Combined mTOR inhibition and OX40 agonism enhances CD8(+) T cell memory and protective immunity produced by recombinant adenovirus vaccines.
abstract: The memory CD8(+) T cell population elicited by immunization with recombinant human adenovirus serotype 5 (rHuAd5) vaccines is composed primarily of effector and effector memory cells (T(EM)) with limited polyfunctionality. In this study, we investigated whether treatment with immunomodulators could enhance and/or redistribute the CD8(+) memory population elicited by rHuAd5. Vaccination in combination with both rapamycin (to modulate differentiation) and an OX40 agonist (to enhance costimulation) increased both the quantity and polyfunctionality of the CD8(+) memory T cell population, with expansion of the T(EM) and memory precursor populations. Furthermore, this intervention enhanced protection against multiple virus challenges. Attenuation of adenovirus transgene expression was required to enable the combination rapamycin + OX40 agonist immunomodulatory treatment to further enhance skewing towards central memory formation, indicating that persistence of antigen expression ultimately limits development of this memory population following rHuAd5 immunization. These results demonstrate that during the expansion phase following adenovirus immunization, the level of mammalian target of rapamycin (mTOR) activity, the amount of costimulation and the duration of antigen availability act together to define the magnitude, phenotype, and functionality of memory CD8(+) T cells. Modulation of these factors can be used to selectively manipulate memory formation.
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Bassett
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Swift
authors.forename: Heather
authors.initials: H
authors.lastname: VanSeggelen
authors.forename: Joanne A
authors.initials: JA
authors.lastname: Hammill
authors.forename: A J Robert
authors.initials: AJ
authors.lastname: McGray
authors.forename: Carole
authors.initials: C
authors.lastname: Evelegh
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wan
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Bramson
mesh_terms: D000256:Adenoviridae / Q000276:immunology*; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D007156:Immunologic Memory / Q000187:drug effects; D051379:Mice; D053278:OX40 Ligand / Q000494:pharmacology; D053262:Receptors, OX40 / Q000819:agonists* / Q000378:metabolism*; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D053278:OX40 Ligand; D053262:Receptors, OX40; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus