title: Persistence of cell-mediated immunity three decades after vaccination with the live vaccine strain of Francisella tularensis.
abstract: The efficacy of many vaccines against intracellular bacteria depends on the generation of cell-mediated immunity, but studies to determine the duration of immunity are usually confounded by re-exposure. The causative agent of tularemia, Francisella tularensis, is rare in most areas and, therefore, tularemia vaccination is an interesting model for studies of the longevity of vaccine-induced cell-mediated immunity. Here, lymphocyte proliferation and cytokine production in response to F. tularensis were assayed in two groups of 16 individuals, vaccinated 1-3 or 27-34 years previously. As compared to naïve individuals, vaccinees of both groups showed higher proliferative responses and, out of 17 cytokines assayed, higher levels of MIP-1β, IFN-γ, IL-10, and IL-5 in response to recall stimulation. The responses were very similar in the two groups of vaccinees. A statistical model was developed to predict the immune status of the individuals and by use of two parameters, proliferative responses and levels of IFN-γ, 91.1% of the individuals were correctly classified. Using flow cytometry analysis, we demonstrated that during recall stimulation, expression of IFN-γ by CD4(+) CCR7(+) , CD4(+) CD62L(+) , CD8(+) CCR7(+) , and CD8(+) CD62L(+) cells significantly increased in samples from vaccinated donors. In conclusion, cell-mediated immunity was found to persist three decades after tularemia vaccination without evidence of decline.
authors: Department of Clinical Microbiology, Umeå University, Umeå, Sweden.
authors: Kjell
authors: K
authors: Eneslätt
authors: Cecilia
authors: C
authors: Rietz
authors: Patrik
authors: P
authors: Rydén
authors: Svenja
authors: S
authors: Stöven
authors: Robert V
authors: RV
authors: House
authors: Lawrence A
authors: LA
authors: Wolfraim
authors: Arne
authors: A
authors: Tärnvik
authors: Anders
authors: A
authors: Sjöstedt
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D005260:Female; D005604:Francisella tularensis / Q000276:immunology*; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D008297:Male; D014613:Vaccines, Attenuated / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D016207:Cytokines; D014613:Vaccines, Attenuated