Fig. 4

Resistance to degradation and immunogenic properties of VSP-pseudotyped VLPs. a Western blot analysis of the action of extreme pHs, T, IE, and SE on VSP1267, VSPH7, VSP9B10, and HA on the surface of different VLPs. The densitometric analysis shows the relative intensity of HA from VLP-HA in comparison to HA from VLP-HA/VSP1267-G. The ratio protein:trypsin (P:T) is expressed as w-w. Dilutions of IE and SE are indicated on top. *p < 0.05; Student ‘s t-test, n = 4 from two independent experiments. b Activation of mTLR-4 and mTLR-2 reporter cell lines by VLP-HA and VLP-HA/VSP1267-G. *p < 0.05, **p < 0.01, ***p < 0.001; one-way ANOVA, Tukey’s multiple comparison test, n = 3 from three independent experiments. c Binding (solid line) and uptake (dotted line) of VLP-VSP-G vs. plain VLP. BMDCs were incubated with fluorescent particles and analyzed by flow cytometry. d In vitro activation of WT and TLR-4 KO BMDCs by VLP-HA or VLP-HA/VSP-G. MFI quantification of CD40 and CD86 expression is shown. **p < 0.01, ***p < 0.001; two-way ANOVA, Bonferroni post-tests, n = 6 from three independent experiments. e Cytokine levels in BMDCs supernatants. Only those cytokines with detectable levels are shown. *p < 0.05, ***p < 0.001; two-way ANOVA, Bonferroni post-tests, n = 6 from three independent experiments. f BMDCs were incubated with VLP-HA/VSP-G treated as freshly purified (Fresh), ten cycles of freezing and thawing (F/T), or kept at −70 °C, 4 °C, or room temperature (RT) for 1 month. CD40 and CD86 levels were measured by flow cytometry. MFI quantification is shown; one-way ANOVA, Tukey’s multiple comparison test, n = 4 from three independent experiments. Values represent mean ± s.e.m. Source data are provided as a Source Data file