Short peptide sequences containing MHC class I and/or class II epitopes linked to nano-beads induce strong immunity and inhibition of growth of antigen-specific tumour challenge in mice

Peptide based vaccines offer practical advantages, but unmodified peptides usually require an adjuvant or delivery vehicle to promote immunogenicity. When peptides containing ovalbumin (OVA) derived CD4 and CD8 T cell epitopes were conjugated to 0.05 μm nano-beads, they gave strong immune responses and inhibition of growth of tumour cells expressing the CD8 T cell epitope with MHC class I. These responses were inducible with both high (50 μg) and low (5 μg) peptide doses after a single immunisation. The helper CD4 T cell epitope was unnecessary for induction of CD8 T cell or tumour challenge responses. However, the CD4 T cell epitope contained a B cell epitope and triggered strong antibody responses. This simple approach offers a convenient experimental tool and a potentially useful clinical method for peptide immunisation.