[Study on gene vaccine pcDNA3-PAc against dental caries by intranasal immunization in rabbits].

Purpose: To investigate the efficiency of pcDNA3-PAc on Japanese long-eared white rabbits by intranasal immunization, and observe the appreciate gene vaccine dose in rabbit immunization.

Methods: Thirty Japanese long-eared white rabbits were randomly divided into 5 groups (6 in each group) as follows: 200, 400, 600 μg pcDNA3-PAc plasmid group; 400 μg pcDNA3 group and inactivated whole-cell vaccine positive control group. The rabbits were immunized twice, and plasmid groups and whole-cell group were coupled Freund's adjuvant with 1:1 ratio. The specific IgG and S-IgA antibodies in serum and saliva were detected with indirect ELISA method. The data was analyzed with SPSS 17.0 software package.

Results: (1) The peak time of the antibodies appeared between 8-10 weeks after the first immunization; (2)The specific antibodies IgG and S-IgA could be detected 2 weeks after immunization;(3)The level of salivary specific S-IgA and serum specific IgG of pcDNA3-PAc were significantly higher than negative groups (P<0.05). The titer of the 200 μg was significantly lower than those of 400 μg and 600 μg group (P<0.05).

Conclusions: (1)The recombinant plasmid pcDNA3-PAc has immunogenicity, which can induce specific immune responses for 14 weeks in rabbits. (2)The results of the present study show that 200 μg, 400 μg and 600 μg are effective immunizational dosage to 1.5 kg Japanese long-eared white rabbits. (3)400 μg and 600 μg pcDNA3-PAc can be considered as the optimal dosage than 200 μg at present experimental condition. Supported by Guizhou Science and Technology Projet of Distinguished Young Talents [2005(0509)], Guizhou College and University Leading Academic Discipline Project [2012(15)] and Zunyi Medical University Project of Distinguished Research Team [2012(12)].