Importance of FcγRIIa and its cytoplasmic tail in ADE-mediated VLP uptake into cells.

<p>(A, B) Fluorescent images of attachment and internalization of VLPs. (C-E) Quantified fluorescent signals of VLP and Dx10. Untreated (Control), CTR IgG-, and ZGP12/1.1-treated DiI-labeled VLPs were inoculated into each Jurkat T cell line and incubated for 30 min on ice. After adsorption, the cells were incubated for 0 h (A, C) or incubated with Alexa647-labeled Dx10 for 2 h at 37°C (B, D, E). VLPs (red) on the cell surface (A, C) and VLPs (red) and Dx10 (green) in the cytoplasm (B, D, E) were monitored by confocal laser scanning microscopy. Scale bars represent 10 μm. Nuclei of cells are visualized with DAPI (blue). The number of VLPs attached to the cell surface (C), the colocalization of VLPs (DiI) and Dx10 (Alexa647) signals (D), and the number and size of Dx10-positive vesicles (E) were quantified. The number and size were calculated by setting the value of FcγRIIa-expressing Jurkat T cells in the presence of ZGP12/1.1-treated VLPs to 100%. The mean and standard deviation of three independent experiments are shown. Statistical analysis was performed using Student’s <i>t</i>-test (*<i>p</i><0.05).