Generation and Characterization of Rotavirus-Like Particle (VLP) Vaccines

In 2011, we generated in E. coli a soluble protein of (i) the P2 (a universal T cell epitope of tetanus toxin)-VP8 subunit of VP4 of human rotavirus P genotype 6 (1076 strain); (ii) the P2-Wa (P genotype 8) VP8-EB NSP4 (amino terminal half of the NSP4) fusion protein; (iii) the P2-Wa VP8-1076 VP8 fusion protein; and (iv) the P2-Wa VP8-Wa VP7 epitope fusion protein. Guinea pigs immunized parenterally with a purified P2-1076 VP8 protein developed high levels of neutralizing antibodies to a homologous virus and low levels of neutralizing antibodies to heterologous strains. Guinea pigs immunized parenterally with a purified P2-Wa VP8-1076 VP8 developed high levels of neutralizing antibodies to both homologous (i.e., Wa and 1076) and heterologous (i.e., DS1 genotype 4) rotavirus strains.<P>Since (i) the combination of the 3 P genotypes (i.e., P genotypes 4, 6 and 8) constitutes more than 95% of all rotavirus P genotypes detectable worldwide today (which are found in association with G genotypes 1, 2, 3, 4, 5, 8, 9 and 12) and (ii) the P2-Wa VP8 can induce high levels of neutralizing antibodies to both homologous P8 and heterologous P4 strains, the P2-Wa VP8-1076 VP8 protein would provide an antigenic coverage to almost all human rotavirus strains of global as well as regional epidemiologic importance. Sublingual (mucosal) immunization of guinea pigs with a purified P2-Wa VP8-EB NSP4 fusion protein did not increase levels of neutralizing antibodies. Sublingual immunization of guinea pigs with this protein mixed with a mucosal adjuvant smLT as well as parenteral immunization of guinea pigs with a purified Wa VP8-Wa VP7 eipitope fusion protein is underway. In addition, we hope to perform a challenge study of P2-Wa VP8 protein in gnotobiotic piglets.