Figure 7:

Immune responses to extended-delivery of influenza vaccines with microneedle (MN) patches in mice. Influenza-specific (a) total IgG, (b) IgGa, and (c) IgG2a. Extended delivery with MN patches induced higher antibody titers compared to all other groups. (d) The ratio of IgG1 to IgG2a was approximately equivalent for all MN groups. Antibody secreting cells for (e) IgG1 and (f) IgG2a were present in higher numbers in the bone marrow of mice vaccinated with extended-delivery than bolus MN-patch vaccination. Lymph nodes of mice receiving extended-delivery MN-patch vaccination had higher percentage of (g) germinal center B cells and (h) T follicular helper cells compared to mice vaccinated by intradermal injection, but not higher than those receiving a MN prime dose followed by placebo patches. (i) Splenocytes that were re-stimulated with antigen secreted higher concentrations of IFN ɣ after extended-delivery vaccination (* p<0.05; ** p<0.01; *** p<0.001; **** p<0.0001). Vaccination groups: bolus intradermal (ID) (Bolus-P-ID), bolus prime + boost on day 28 given ID (Bolus-P+B-ID) bolus MN patch (Bolus-P-MN), bolus MN patch followed by placebo MN patches for the remainder of the 28 days (Bolus-P-MN + ED-Placebo-MN), 28-day extended delivery by MN patch (ED-28day-MN) and placebo MN patches (Bolus-Placebo-MN), which were interpreted as the negative control group. Serum antibody titers and cellular responses were measured at day 35, which was one week after final vaccination for the ED group and one week after the boost. Total antigen delivered was held constant for each dose at 1 μg of inactivated influenza vaccine (H1N1 A/Brisbane/10/10). Data show mean ± S.D. based on 8 replicates.