Fig. 4
Analysis of the humoral response towards Lassa virus glycoprotein. C57BL/6 mice were immunized IM in the gastrocnemius muscle with either 10 μg of β-propiolactone inactivated viral particles in PBS or adjuvanted with 5 μg of GLA, a TLR-4 agonist formulated in 2% of stable emulsion (SE); LASSARAB+GLA-SE, LASSARAB, FILORAB1 groups) and boosted two times with the same amount on day 7 and 28 (a). Immunizations with replication-competent viruses were executed with a single time inoculation of 106 ffu or pfu virus IM in the gastrocnemius (rc-LASSARAB; rc-FILORAB1 groups and rVSV-GPC). b The EC50 values (obtained from the 4PL regression ELISA curve) of the total IgG titers against LASV GPC are plotted since day 0 until day 42. Error bars are representative of the standard error mean (SEM) and is calculated from 15 mice per group. Statistical significance was calculated by using 2-way ANOVA–post-hoc Tukey’s Honest Significant Difference Test. c ELISA of total IgG against LASV GPC of all day 42 groups are shown for all immunized groups. ELISA curves are generated from 4PL regression. Error bars are representative of the SEM of OD 490 values (five mice per group, in triplicates). d Day 35 EC50 antibody titer of IgG sub-isotype (IgG2c and IgG1) against LASV GPC of sera from LASSARAB+GLA-SE and LASSARAB group was analyzed. Error bars are the SEM of a total of five mice per group and statistical significance by 2-way ANOVA (post-hoc Tukey’s Honest Significant Difference Test). e The ratios of the respective EC50 antibody titers IgG1/IgG2c are plotted and the F test was applied to check for variance difference (p < 0.001). (****P < 0.0001; ***P < 0.001; **P < 0.01; *P < 0.05)
