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Updated: Jul 7, 2026

Evaluation of Host-Pathogen Responses and Vaccine Efficacy in Mice
Published on: February 22, 2019
Immunogenicity and efficacy of a DNA vaccine in aged mice
D M Klinman1, J Conover, E T Bloom
1Section of Retroviral Immunology, Division of Viral Products, fCenter for Biologics Evaluation and Research, Food and Drug Administration, Bethesda 20892, USA. klinman@a1.cber.fda.gov
Abstract:
The immunogenicity and protective efficacy of a DNA vaccine encoding the circumsporozoite protein of the Plasmodium yoelii malaria parasite was evaluated in young (2 months) versus aged (>26 months) BALB/c mice. The primary and secondary humoral immune response of aged mice was 19- and 7-fold lower, respectively, than that of similarly treated young animals (p < .01). Cytotoxic T lymphocyte activity in aged mice was also lower than in younger animals. The vaccine response of aged animals was characterized by a 6-fold increase in interleukin-4 and a 3-fold increase in interferon-gamma (IFN-gamma) secreting cells, whereas in young animals immunization only stimulated the production of the type 1 cytokine IFN-gamma. Overall, 80% of young vaccinated mice were protected from subsequent challenge with live malaria sporozoites whereas only 40% of aged mice were protected. These results are the first to demonstrate that DNA vaccination induces less effective immunity in aged than young animals.

