[A fusion protein of rotavirus VP6 and cholera toxin B subunit: expression in Escherichia coli and analysis of biological activities].

Rotavirus infection is a major cause of dehydrating diarrhea in infants worldwide. The non-toxic cholera toxin B subunit(CTB), known as an immunomodulatory carrier, might help to stimulate mucosal immune response when coupled to rotavirus antigens in oral immunization. Here we report for the first time the construction of a translational fusion of CTB gene 5' to the VP6 gene of a human rotavirus A(field strain T114), and expression of the CTB-VP6 fusion protein in E. coli BL21(DE3). The expressed fusion protein has a molecular weight of 56 kD, as expected, and accounts for about 15% of the total E. coli protein. Western blottings with the hyperimmune serum against rotavirus strain WA and the antibody against cholera toxin indicated that the fusion protein retains the antigenicity identical to the native CTB and VP6. The GM1-ELISA analysis proves that the renatured CTB-VP6 has strong affinity for GM1 ganglioside.