OBJECTIVETo detect the immunoreactivity of targeted fusion anti-caries DNA vaccine pGJA-P in vitro, and the ability to enhance the immune responses compared with the non-targeted fusion anti-caries DNA vaccine pGLUA-P.

METHODSThe CHO cells were transfected with pGJA-P and the expression of recombinant protein in cultured supernatants were detected using Western blotting. 5 to 6-month-old female Japanese rabbits were immunized with either pGJA-P or pGLUA-P via either intramuscular injection (i.m.) or intranasal route (i.n.). The sera and saliva were collected and the antibody responses were checked by ELISA. The effect of immune sera on the synthesis of water-insoluble glucan by glucosyltransferase of S. mutans was examined.

RESULTSThe expressed protein could response to specific anti-GTF antibody. The antibody responses in serum generated by pGJA-P via i.m. were significantly higher than those generated by pGLUA-P (P < 0.01). The antibody responses in saliva generated by pGJA-P via i.n. were significantly higher than those generated by pGLUA-P (P < 0.01). The higher mucosal antibody response induced by pGJA-P via i.m. compared with pGLUA-P (P < 0.01) was detected. The immune sera of rabbits immunized by pGJA-P via i.m. most significantly inhibited the synthesis of water-insoluble glucan by glucosyltransferase.

CONCLUSIONSThe recombinant protein expressed by pGJA-P had the immunoreactivity to anti-GTF antibody. pGJA-P could induce faster and higher specific mucosal SIgA antibody responses via i.n. or serum IgG antibody responses via i.m. compared with non-targeted DNA vaccine, pGLUA-P. High titres of specific mucosal antibodies were found in rabbits immunized with pGJA-P via i.m. The immune sera of rabbits immunized by pGJA-P via i.m. displayed the ability of inhibiting the synthesis of water-insoluble glucan by glucosyltransferase.