The adjuvant effect of including CaP in PCMCs was confirmed for both antigens ( Table 1). This was particularly marked for the anti-CyaA* response as only one mouse in the 0% CaP group produced a detectable anti-CyaA* IgG titre at each time point investigated. Increasing the CaP content did not significantly further increase the antigen-specific IgG titres or alter the duration of antibody response. The attempted prime-boost BMS-754807 cell line formulation failed to enhance immunogenicity compared to other CaP PCMC formulations. J774.2 cells were incubated with equal amounts of either soluble BSA-FITC or BSA-FITC formulated

as 0% or 8% CaP PCMCs. Uptake of fluorescent antigen was visualised by confocal laser-scanning microscopy (Fig. 5, panels A–C) and quantified by flow cytometry (panels D–F). Confocal microscopy showed that soluble BSA-FITC was poorly phagocytosed, with J774.2 cells containing low levels of fluorescence (Fig. 5A). In contrast, loading BSA-FITC onto PCMCs increased phagocytosis, with cells displaying punctate regions of green fluorescence (Fig. 5B) and this was further enhanced with CaP PCMCs (Fig. 5C). These observations were confirmed by flow cytometry. The P2 daughter population was derived

from the parent population P1. The increase in MFI of the P2-gated population of the cells upon exposure OSI-906 manufacturer to BSA-FITC PCMCs (Fig. 5E) and the further increase in the presence of CaP-modified PCMCs (Fig. 5F) indicates a greater phagocytosis of these particles compared to soluble BSA-FITC (Fig. 5D). These results, in combination with published data, demonstrate that PCMC formulations are suitable for vaccine applications and may address problems associated with current vaccines. Moreover, CaP PCMCs were shown to be immunogenic and to promote a more

before mixed Th1/Th2 response in comparison to traditional formulations and to soluble PCMCs [5] and [7]. Modification of the surface of PCMC with an outer layer of CaP altered the particle morphology from planar discs to rod-like structures and significantly decreased the rate of antigen release in vitro. PCMCs without CaP released antigen almost immediately in aqueous buffers whereas increasing the CaP loading progressively decreased the rate of antigen release. This is consistent with release being controlled by dissolution of an outer layer of CaP, the thickness of which is expected to increase with CaP loading. This suggests that CaP PCMCs would potentially show enhanced immunogenicity due to a depot effect in vivo as has been proposed for other adjuvants [2] and [15]. Surprisingly, mice immunised with DT formulated into soluble PCMCs showed enhanced immunogenicity compared to soluble DT antigen. The in vitro solubility data indicated that this enhanced immunogenicity was not due to a depot effect.