FIG 7.

SFTS virus NSs-positive extracellular vesicles can mediate receptor-independent transmission of SFTS virus. HeLa cells were pretreated with anti-CD63 antibody (A), IgG control (B), anti-SFTS virus antibody (C), or PBS (D) prior to infection with the purified extracellular vesicles, SFTS virus, or the SFTS virus preparation subjected to the immune-negative selection and the antibody incubation step described in Fig. 6. Supernatants were harvested at 0, 24, 48, and 72 hpi, and a plaque assay was performed. The dashed line indicates the limit of detection (4 PFU/ml). All experiments were repeated three times with consistent results. The results presented are expressed as means + the SEM. Asterisks indicate statistically significant differences (P < 0.05) between the indicated groups.