Background: Prevention of infectious diseases is of high priority in the rapidly aging population. Unfortunately, vaccine responses in the elderly are frequently diminished. Timely vaccination of middle-aged adults might improve the immune responses to vaccines, although knowledge on pathogen-specific immune responses and factors affecting these responses, in middle-aged adults is currently limited. We thus investigated the immune responses after vaccination with Zostavax consisting of live-attenuated varicella zoster virus (VZV).
Methods: Blood samples were taken pre-, 14 days, 28 days, and 1 year after a primary VZV vaccination (Zostavax) at middle age (N = 53, 50-65 years of age). VZV-specific IFNγ-producing cells were measured by ELISpot, activated T-cells by flow cytometry, antibody levels and cytokine responses by fluorescent bead-based multiplex immunoassays, and whole blood cellular kinetics by TruCOUNT analysis.
Results: Robust short-term enhancement of the VZV-specific IFNγ-producing cell numbers was observed post-vaccination in the middle-aged adults. Remarkably, long-term enhancement of VZV-specific IFNγ-producing cell numbers was induced only in participants with low numbers of VZV-specific pre-vaccination IFNγ-producing cells, who were significantly older. These participants also showed enhancement of VZV-specific activated CD4 T-cells, contrary to "exhausted" VZV-specific CD8 T-cells in participants with high numbers of VZV-specific pre-vaccination IFNγ-producing cells. Finally, a high CD4/CD8 T-cell ratio was associated with low numbers of pre-vaccination VZV-specific IFNγ-producing cells.
Conclusion: These results suggest that adults in their early sixties, who showed a high CD4/CD8 T-cell ratio and low numbers of VZV-specific IFNγ-producing cells, benefit from VZV vaccination. This provides important knowledge on factors affecting VZV-specific immune responses in middle-aged adults as well as for strategies to strengthen immunity before reaching old age.

Additional Metadata
Keywords Cytokines, Middle-aged adults, Preexisting immunity, T-cells, Vaccination, Varicella zoster virus
Persistent URL dx.doi.org/10.3389/fimmu.2018.00046, hdl.handle.net/1765/104314
Journal Frontiers in Immunology
Citation
van der Heiden, M. (Marieke), de Rond, L.G.H, van Zelm, M.C, Berbers, G.A.M, Boots, A.M.H, & Buisman, A.-M. (2018). Age-dependent pre-vaccination immunity affects the immunogenicity of varicella zoster vaccination in middle-aged adults. Frontiers in Immunology, 9(JAN). doi:10.3389/fimmu.2018.00046