Effects of adjuvants on IgG subclasses elicited by virus-like Particles

BACKGROUND: Virus-Like Particles (VLPs) represent an efficient strategy to present and deliver conformational antigens to the immune system, inducing both arms of the adaptive immune response. Moreover, their particulate structure surrounded by cell membrane provides an adjuvanted effect to VLP-based immunizations. In the present study, the elicitation of different patterns of IgG subclasses by VLPs, administered in CpG ODN1826 or poly(I:C) adjuvants, has been evaluated in an animal model. RESULTS: Adjuvanted VLPs elicited a higher titer of total specific IgG compared to VLPs alone. Furthermore, while VLPs alone induced a balanced T(H)2 pattern, VLPs formulated with either adjuvant elicited a T(H)1-biased IgG subclasses (IgG2a and IgG3), with poly(I:C) more potent than CpG ODN1826. CONCLUSIONS: The results confirmed that adjuvants efficiently improve antigen immunogenicity and represent a suitable strategy to skew the adaptive immune response toward the differentiation of the desired T helper subset, also using VLPs as antigen.