TLR expression and NK cell activation after human yellow fever vaccination

Vaccine. 2009 Sep 18;27(41):5543-9. doi: 10.1016/j.vaccine.2009.07.028. Epub 2009 Jul 30.


The yellow fever vaccine is very effective with a single injection conferring protection for at least 10 years. Recent evidence suggests that the innate immune cells activated through Toll-like receptors (TLRs), are critical determinants of the robustness of the adaptive response. Therefore, we investigated the NK cell status in eight healthy volunteers after vaccination with YF 17DD virus. Shortly after vaccination, we observed increased expression of TLR-3 and TLR-9 in NK cells and markers such as CD69, HLA-DP-DQ-DR, CD38 and CD16. The up-regulation of CD69 was positively correlated with the presence of TLRs throughout the post-vaccination period and the circulating IFN-gamma was significantly augmented. These results suggest that TLRs may play an important role in NK cell activation during the immune response to vaccination, indicating a potential role for NK cells in helping the development of long-lasting protective memory.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, CD / biosynthesis
  • Female
  • HLA Antigens / biosynthesis
  • Humans
  • Killer Cells, Natural / immunology*
  • Lymphocyte Activation*
  • Male
  • Toll-Like Receptors / biosynthesis*
  • Up-Regulation
  • Yellow Fever / prevention & control*
  • Yellow Fever Vaccine / immunology*
  • Young Adult


  • Antigens, CD
  • HLA Antigens
  • Toll-Like Receptors
  • Yellow Fever Vaccine