3.4 immunogenicity of HA-coated microstructure patches.
The immunogenicity of HA-coated microstructure patches was evaluated in hairless guinea pigs.A moderate increase in HI titers was observed after the first immunization(See supplementary fig.1),and a large increase in HI titers was seen in second immunization, consistent with result observed with IM influenza immunization in previously influenza-naive experimental animals.
The serum HI titers two weeks after the second immunization are shown in fig.5.
After two immunization, serum HI titers for all immunized group were greater than 40,indicating greater than a 4-fold increase compared to control.
The HI titers elicited by two immunizations with coated microstructure patches were comparable to those elicited by IM injection of the unprocessed trivalent influenza vaccine and IM injection of desorbed antigens from the patch.
No weight loss or skin reactions were observed for any of the group after immunization.
The patches used for administration in the in vivo study were also analyzed by RP-HPLC for initial HA content and residual HA content after application.
During the priming immunization,65.1% of the coated antigen dose was delivered; during the boost,70.7% was delivered(table 3).
Based on the SRID assay of the HA content. This corresponds to 24g of HA delivered in the priming dose, and 19 g. delivered in boost.
Given that the goal of the aspect of the work was demonstrate immune response in an animal model, wear time of the microstructure patches was not optimized and delivery of 70% of the coated antigen was considered acceptable for the experimental goals.
Supplementary data associated with this article can be found in the online version, at http://dx.doi.org/10.1016/j.vaccine.2013.01.050.