Article: CD11a and CD49d enhance the detection of antigen-specific T cells following human vaccination
Authors: Christiaansen AF, Dixit UG, Coler RN, Marie Beckmann A, Reed SG, Winokur PL, Zimmerman MB, Varga SM, Wilson ME.
Journal: Vaccine. 2017 Jul 24;35(33):4255-4261
Determining the efficacy of human vaccines that induce antigen-specific protective CD4 T cell responses against pathogens can be particularly challenging to evaluate. Surface expression of CD11a and CD49d has been shown to identify antigen-specific CD4 T cells against viral pathogens in mice. We hypothesized that CD11a and CD49d would also serve as markers of human antigen-specific T cells responding to vaccination.
A phase I vaccine trial enabled us to evaluate a novel gating strategy based on surface expression of CD11a and CD49d as a means of detecting antigen-specific, cytokine producing CD4 and CD8 T cells induced after vaccination of naïve individuals against leishmaniasis. Three study groups received LEISH-F3 recombinant protein combined with either squalene oil-in-water emulsion (SE) alone, SE with the synthetic TLR-4 ligand glucopyranosyl lipid adjuvant (GLA-SE), or SE with Salmonella minnesota-derived monophosphoryl lipid A (MPL-SE). Individuals were given 3 vaccine doses, on days 0, 28 and 168.
Starting after the first vaccine dose, the frequency of both CD11ahiCD49d+ CD4 and CD11ahiCD49d+ CD8 T cells significantly increased over time throughout the 24-week trial. To confirm the role of CD11ahiCD49d+ expression in the identification of the antigen-specific T cells, cytokine production was measured following LEISH-F3 stimulation. All of the IFN-γ, TNF-α, and IL-2 producing cells were found within the CD11ahiCD49d+ population.
Our results suggest that the change in the frequency of CD11ahiCD49d+ T cells can be used to track antigen-specific CD4 and CD8 T cell responses following T cell-targeted vaccination.
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