Blockage of regulatory T cells augments induction of protective immune responses by influenza virus-like particles in aged mice

Microbes Infect. 2017 Dec;19(12):626-634. doi: 10.1016/j.micinf.2017.08.013. Epub 2017 Sep 9.


Elderly humans over 65 years old are at great risk to pathogenesis by influenza virus infection. However, although influenza vaccines provide effective protection in healthy young adults, protection of elderly adults is substantially lower even with a good match between the vaccine and the circulating influenza virus. To gain insight of the underlying mechanism for the reduced immunogenicity of influenza vaccines in the aged population, we investigated immunogenicity of influenza virus-like particle vaccines in aged mice, which represent a useful model for studying aging associated impairment in immune responses. Specifically, we investigated the effect of inhibiting regulatory T cells in aged mice on induction of protective immune responses by influenza vaccines. Our results showed that injecting anti-CD25 antibodies could down-regulate CD25 on the surface of regulatory T cells and significantly increase the levels of antibody responses induced by VLP immunization in aged mice. Further, the profiles of antibody responses were also changed towards Th1 type by regulatory T cell blockage in aged mice. Moreover, aged mice that were treated by anti-CD25 antibodies prior to vaccination were more effectively protected against lethal influenza virus challenge.

Keywords: Aging; Influenza; Regulatory T cell; Vaccine.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / immunology*
  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibodies, Viral / blood*
  • Antibodies, Viral / immunology
  • Antibody Formation / immunology
  • Female
  • Immunogenicity, Vaccine / immunology
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / immunology
  • Mice
  • Mice, Inbred BALB C
  • Orthomyxoviridae Infections / immunology*
  • Orthomyxoviridae Infections / prevention & control*
  • Orthomyxoviridae Infections / virology
  • T-Lymphocytes, Regulatory / immunology*
  • Th1 Cells / immunology
  • Vaccination
  • Vaccines, Virus-Like Particle / immunology*


  • Antibodies, Monoclonal
  • Antibodies, Viral
  • Immunoglobulin G
  • Influenza Vaccines
  • PC61 monoclonal antibody
  • Vaccines, Virus-Like Particle