Fig. 2. Immune responses to prime/boost intramuscular immunization with FEN-CRM197 are enhanced in magnitude and longevity with dmLT and LTA1 adjuvants.
Groups of Balb/c mice (n = 3–5) were left naïve or immunized IM with 5 μg FEN-CRM ± 150 μg alum, 0.1 μg dmLT, or 5 μg LTA1 on weeks 0 and 3. Two-weeks later (week 5) or six-weeks later (week 9) serum, spleen, and bone-marrow was collected for antibody evaluations. a Schematic of the immunization schedule. b Raw ELISA data for week 5 serum anti-CRM or anti-FEN serum IgG expressed as absorbance. Two anti-FEN ELISA coating antigens were used as indicated by FEN-BSA or FEN-TT. c Compiled week 5 and 9 serum anti-CRM or anti-FEN (coating antigen indicated) serum IgG. d Representative anti-FEN (FEN-TT coating antigen) IgG/IgA ELISPOT images from bone-marrow of week 5 immunized mice. Blue spots indicate IgG and red spots IgA ASCs. e Compiled anti-FEN IgG ASC per 1e6 cells from bone marrow. f Anti-FEN IgG memory B cells per 106 cells differentiated in culture from immunized splenocytes from week 9 post immunization. Bars at mean + s.e.m. with significance determined by ANOVA paired with Bonferroni post-hoc test as shown (*P < 0.05, **P < 0.01, ***P < 0.001).