IMMUNOGENICITY OF POLIOVIRUS B-CELL AND T-CELL EPITOPES PRESENTED BY HYBRID PORCINE PARVOVIRUS PARTICLES

We have analysed the potential capacity of hybrid porcine parvovirus ( PPV) capsids to present foreign epitopes to the immune system. Foreign sequences were introduced into the N and C termini of PPV VP2, which was previously shown to assemble spontaneously into parvovirus-like pa rticles. The integrity of the C terminus was shown to be essential for preserving the structure of the capsid and therefore could not be use d for epitope fusion. In contrast, insertion of sequences correspondin g to T and B cell poliovirus epitopes in the N terminus did not alter the formation of particles. Moreover, the chimeric capsids containing the C3:T epitope were able to induce a T cell response in vivo. Howeve r, hybrid particles containing the C3:B epitope fused to the N terminu s did not induce any peptide-specific antibody response, suggesting th at the inserted B cell epitope was not exposed at the surface of the p articles. These results show that the N terminus in PPV empty capsids is not an adequate site for insertion of B cell epitopes, but may be u seful for T cell epitope presentation and suggest that the N terminus is located in an internal position.