Fig. 4

A single dose of rVSV-SFTSV/AH12-GP or rVSV-eGFP-HRTV-GP elicits complete protection against lethal dose challenge with SFTSV Wuhan strain in IFNAR^−/− C57/BL6 mice. a, b Susceptibility of IFNAR^−/− mice to SFTSV. Six-to-eight-week-old mice (n = 5/group), were i.p. inoculated with 2 × 10¹ to 2 × 10⁴ FFU of SFTSV Wuhan strain and then monitored for weight loss a and mortality b. DMEM was used as control. Data are representative of three independent experiments (error bars represent SD). c, d IFNAR^−/− mice (n = 5/group), were immunized with the indicated amount (PFU) of rVSV-SFTSV/AH12-GP, rVSV-eGFP-HRTV-GP, rVSV-eGFP-HTNV-GP, or DMEM control and then challenged with 2 × 10⁴ FFU of SFTSV Wuhan strain at 30 days post immunization. Weight loss c and mortality d were monitored for indicated time. Overlapped lines were indicated on the right end. e. Mice immunized with 2 × 10⁴ PFU of rVSV-SFTSV/AH12-GP or rVSV-eGFP-HTNV-GP were tested for viremia after SFTSV challenge as above. Above data are representatives of three independent experiments (error bars represent SD). Significance was calculated using a multiple t test—one per row between control group and experimental groups (*P-value < 0.05; **P-value < 0.01; ****P-value < 0.0001). f, g Immunization route does not affect the efficacy of rVSV-SFTSV/AH12-GP. IFNAR^−/− mice (n = 5/group), were immunized with 1 × 10⁴ PFU of rVSV-SFTSV/AH12-GP by intraperitoneal, intravenous, subcutaneous, and intranasal route, and then i.p. challenged with 2 × 10⁴ FFU of SFTSV Wuhan strain at 30 days post immunization. Control group was not immunized (Con.). Weight loss f and mortality g were monitored for indicated time. Overlapped lines are indicated on the right end. Above data are representatives of two independent experiments (error bars represent SD). h, i Passive transfer of sera from rVSV-SFTSV/AH12-GP immunized mice confers protection in naive mice. Sera were prepared from IFNAR^−/− mice immunized with 2 × 10⁴ PFU of rVSV-SFTSV/AH12-GP or rVSV-eGFP-HTNV-GP at 30 days post immunization. Five serum samples of each group were randomly injected into five naive IFNAR^−/− mice (i.p.); 24 h later, recipient mice were challenged with 2 × 10³ FFU of SFTSV Wuhan strain (i.p.) and monitored for weight loss h and mortality i. Above data are representatives of three independent experiments