title: Heterologous plasmid DNA prime-recombinant human adenovirus 5 boost vaccination generates a stable pool of protective long-lived CD8(+) T effector memory cells specific for a human parasite, Trypanosoma cruzi.
abstract: Recently, we described a heterologous prime-boost strategy using plasmid DNA followed by replication-defective human recombinant adenovirus type 5 as a powerful strategy to elicit long-lived CD8(+) T-cell-mediated protective immunity against experimental systemic infection of mice with a human intracellular protozoan parasite, Trypanosoma cruzi. In the present study, we further characterized the protective long-lived CD8(+) T cells. We compared several functional and phenotypic aspects of specific CD8(+) T cells present 14 or 98 days after the last immunizing dose and found the following: (i) the numbers of specific cells were similar, as determined by multimer staining or by determining the number of gamma interferon (IFN-γ)-secreting cells by enzyme-linked immunospot (ELISPOT) assay; (ii) these cells were equally cytotoxic in vivo; (iii) following in vitro stimulation, a slight decline in the frequency of multifunctional cells (CD107a(+) IFN-γ(+) or CD107a(+) IFN-γ(+) tumor necrosis factor alpha positive [TNF-α(+)]) was paralleled by a significant increase of CD107a singly positive cells after 98 days; (iv) the expression of several surface markers was identical, except for the reexpression of CD127 after 98 days; (v) the use of genetically deficient mice revealed a role for interleukin-12 (IL-12)/IL-23, but not IFN-γ, in the maintenance of these memory cells; and (vi) subsequent immunizations with an unrelated virus or a plasmid vaccine or the depletion of CD4(+) T cells did not significantly erode the number or function of these CD8(+) T cells during the 15-week period. From these results, we concluded that heterologous plasmid DNA prime-adenovirus boost vaccination generated a stable pool of functional protective long-lived CD8(+) T cells with an effector memory phenotype.
authors.affiliation: CTCMol, UNIFESP, Escola Paulista de Medicina, Rua Mirassol 207, São Paulo, SP, Brazil 04044-010.
authors.forename: Paula Ordonhez
authors.initials: PO
authors.lastname: Rigato
authors.forename: Bruna C
authors.initials: BC
authors.lastname: de Alencar
authors.forename: José Ronnie C
authors.initials: JR
authors.lastname: de Vasconcelos
authors.forename: Mariana R
authors.initials: MR
authors.lastname: Dominguez
authors.forename: Adriano F
authors.initials: AF
authors.lastname: Araújo
authors.forename: Alexandre V
authors.initials: AV
authors.lastname: Machado
authors.forename: Ricardo T
authors.initials: RT
authors.lastname: Gazzinelli
authors.forename: Oscar
authors.initials: O
authors.lastname: Bruna-Romero
authors.forename: Mauricio M
authors.initials: MM
authors.lastname: Rodrigues
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D014355:Chagas Disease / Q000276:immunology* / Q000517:prevention & control*; D005260:Female; D005434:Flow Cytometry; D005822:Genetic Vectors; D007117:Immunization, Secondary / Q000379:methods; D007156:Immunologic Memory / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010957:Plasmids / Q000276:immunology; D016052:Protozoan Vaccines / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000276:immunology*; D014611:Vaccination / Q000379:methods*; D019444:Vaccines, DNA / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D016052:Protozoan Vaccines; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic