Protection by universal influenza vaccine is mediated by memory CD4 T cells

Publication date: 5 July 2018
Source:Vaccine, Volume 36, Issue 29
Author(s): Sophie A. Valkenburg, Olive T.W. Li, Athena Li, Maireid Bull, Thomas A. Waldmann, Liyanage P. Perera, Malik Peiris, Leo L.M. Poon
There is a diverse array of influenza viruses which circulate between different species, reassort and drift over time. Current seasonal influenza vaccines are ineffective in controlling these viruses. We have developed a novel universal vaccine which elicits robust T cell responses and protection against diverse influenza viruses in mouse and human models. Vaccine mediated protection was dependent on influenza-specific CD4⁺ T cells, whereby depletion of CD4⁺ T cells at either vaccination or challenge time points significantly reduced survival in mice. Vaccine memory CD4⁺ T cells were needed for early antibody production and CD8⁺ T cell recall responses. Furthermore, influenza-specific CD4⁺ T cells from vaccination manifested primarily Tfh and Th1 profiles with anti-viral cytokine production. The vaccine boosted H5-specific T cells from human PBMCs, specifically CD4⁺ and CD8⁺ T effector memory type, ensuring the vaccine was truly universal for its future application. These findings have implications for the development and optimization of T cell activating vaccines for universal immunity against influenza.



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