Abstract:

Objective　The purpose of this study is to examine the levels of salivary SIgA and serum IgG induced by pcDNA3-pac and pcDNA3-gtfB immunization, so as to testify the antigenity of the two gene vaccines.Methods　36 28-day-old Wistar rats were divided into 6 groups, among which 3 experimental groups were vaccinated with pcDNA3-pac, pcDNA3-gtfB or pcDNA3-pac combined with pcDNA3-gtfB, respectively, one positive control was vaccinated with inactive whole cell ofS.mutans JBP and other two negative controls were injected with the vector pcDNA3 or PBS buffer, respectively. All vaccines and materials were delivered with 100μg by submandibular gland injection for 3 times. Then the restricted bacterial model of ratwas construct- ed. Following that all ratswere fedwith cariogenic dietKeyes 2000#for 3 months, saliva and serum sampleswere collected to as- say SIgA or IgG levels by ELASA.Results　The salivary S-IgA levels both in pcDNA3-pac combined with pcDNA3-gtfB group and inactiveS.mutanscell group were higher than others (P<0·01). In groups of pcDNA3 and PBS buffer, they were lowest (P<0·01). The serum IgG levels in the three experimental groups and positive control were higher than that in negative control (P<0·05). It was important that salivary SIgA in groups of gene vaccine and inactiveS.mutansvaccination reached its peak at the 11th week after the first inoculation and kept until the end of the study.Conclusion　Both pcDNA3-pac and pcDNA3-gtfB can express immunogenic protein and induce immune responses of mucosal and humoral immune system in gnobobiotic rats. It is also indicated that the joint gene vaccines immunization is an optimal choice for anticaries strategy.

Key words: Streptococcus mutans, glucosyltransferases, surface protein antigen, gene vaccine