Pattern of activation of human antigen presenting cells by genotype GII.4 norovirus virus-like particles

BACKGROUND: Virus-like particles (VLPs) from an Italian GII.4 norovirus strain were used to investigate activation and maturation of circulating antigen presenting cells (APCs) of human origin. METHODS: Peripheral blood mononuclear cells (PBMCs) isolated from five healthy subjects were pulsed ex vivo with VLPs, and stained with a set of monoclonal antibodies (MAbs) for phenotypic analysis by flow cytometry. Cytokine release in cell supernatants was investigated by ELISA. RESULTS: Norovirus VLPs induced activation and maturation of circulating APCs derived from the five donors, as well as production of IL-6, IFN-γ and TNF-α cytokines. CONCLUSIONS: The present results suggest that VLPs can activate antigen presenting cells for an efficient induction of the adaptive immune response.