Endotoxin levels of CPMV and eCPMV particles. 1, eCPMV/p directly after purification; 2, eCPMV/p after purification and heat precipitation; 3, eCPMV/p with endotoxins removed; 4, eCPMV with endotoxins removed, followed by heat precipitation; 5, CPMV directly after purification; 6, CPMV after purification and heat precipitation; 7, CPMV with endotoxins removed; 8, CPMV with endotoxins removed, followed by heat precipitation. The significance level was calculated using one-way analysis of variance (ANOVA) and Tukey’s multiple-comparison test. ****, P < 0.0001; n.s., not significant.