Virus-like particles and α-galactosylceramide form a self-adjuvanting composite particle that elicits anti-tumor responses

Virus-like particles (VLP) are effective vehicles for delivery of heterologous antigen to antigen-presenting cells. However VLP alone are insufficiently stimulatory to generate the signals required to facilitate effective priming of naive T cells. We show that the VLP derived from rabbit hemorrhagic disease virus can bind the galactose-containing adjuvant alpha-galactosylceramide to form a composite particle for co-delivery of antigen and adjuvant to the same antigen-presenting cell. Vaccination with VLP and alpha-galactosylceramide activated splenic iNKT cells to produce IFN-gamma and IL-4, led to the generation of antigen-specific T cells that protected prophylactically against subcutaneous tumor challenge, and was more effective at generating anti-tumor immune responses than either component individually. These data demonstrate a novel method for immunopotentiating VLP to increase their efficacy in the generation of anti-tumor responses via the innate ligand recognition properties of calicivirus-derived nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.