Fig. 4: No difference in systemic immunogenicity between the LNP formulation and that of soluble FPM2e.
a Balb/c mice were immunized i.n at 10 days apart with 2 or 3 doses with 5 μg FPM2e or FPM2e:LNP and serum M2e-specific IgG antibody titers were assessed by ELISA at 10 days after the last dose. Log10 titers are given as means ± SD of 5 mice in each group and 3 independent experiments giving similar results. b–f Recall responses to M2e peptide in cultured splenocytes following 3 i.n immunizations with a dose range of FPM2e or FPM2e:LNP, as indicated in B. Or assessed after 3 i.n immunizations with 5 μg of FPM2e, FPM2e:LNP, inactive FPM2e or inactive FPM2e:LNP, as indicated (c–f). 3H-Thymidine uptake was assessed and values are given for proliferating CD4+ T cells in triplicates as mean cpm±SEM of groups of 5 mice. This is one representative experiment out of 3 independent experiments giving similar results (b–d). The production of IFN-γ (left panel) or IL-17A (right panel) in culture supernatants was assessed by ELISA and given as pg/ml ± SD (e). Individual IFN-γ (left panel) or IL-17A (right panel) producing CD4+ T cells in culture were assessed by ELISPOT and given as mean SFC/2 × 105 cells ± SD. g Serum M2e-specific total IgG (left panel), IgG1 (middle panel), or IgG2a (right panel) antibodies were determined by ELISA in groups as indicated and given as mean log10 titers ± SD of one representative experiment out of 3 giving similar results. Statistical significance was calculated by unpaired t test and p values are given as *p < 0.05, **p < 0.01, and ***p < 0.005.
