Shan Chen, David Roumanes, Maria T. Arevalo, Yanping Chen and Mingtao Zeng
Seasonal influenza vaccine efficacy is measured by the vaccine’s ability to elicit strain-specific antibody responses. Every year, resources are allocated into formulating new influenza vaccines. Candidate vaccines utilizing memory T-cells may afford long-term protection. Our study characterizes the human CD4+ memory T-cell response to influenza virus. Intracellular cytokine staining assay was used to assess T-cell production of several cytokines (IFN-γ, IL-2, TNF-α, IL-4, IL-5, and IL-17) found in human peripheral blood mononuclear cells after stimulation with influenza antigens. Production of Th1 cytokines (IFN-γ, TNF-α, and IL-2) was significant in activated CD4+ T-cells after stimulation, whereas Th2 cytokine secretion remained unchanged. In addition, a significant increase in multifunctional CD4+ T-cells that simultaneously secreted combinations of IL-2, IFN-γ, and TNF-α was observed. Our studies have revealed that CD4+ T-cell responses against influenza are Th1-biased, raising the possibility of identifying these populations as targets for successful influenza vaccination