Biodistribution and expression of targeted fusion anti-caries DNA vaccine pGJA-P/VAX in mice

OBJECTIVE: To study the biodistribution and expression of anti-caries DNA vaccine pGJA-P/VAX in mice models following intranasal (i.n.) and intramuscular (i.m.) immunization. METHODS: pGJA-P/VAX and pVAX1 were administrated i.n. and i.m. to mice, respectively. Blood and organs were harvested and then genomic DNA was extracted. mRNA in the original tissues and draining lymph nodes was isolated. The in vivo fate of plasmid DNA in these samples was evaluated with real-time quantitative polymerase chain reaction (PCR). RESULTS: The ratio of the area under the curve (AUC) and maximum concentration (Cmax) after i.n. immunization were higher than that after i.m. injection. At 1 day post i.n. immunization, the localization of plasmid to the heart, spleen and lung was notable compared with that to the nasal mucosa. At 2 days, for i.n. immunization, the concentration value of plasmid in the mucosa-associated lymphoid tissues such as lung, kidney and gastrointestine had increased and was greater than that via i.m. injection. At later time points, the plasmid was primarily in the original tissues and draining lymph nodes. mRNA expression was observed in the topical tissues up to 7 days and in the draining lymph nodes for at least 3 days. CONCLUSIONS: These results indicate that the distribution of pGJA-P/VAX was widespread in vivo, and the expression was significant in the inoculation tissue and draining lymph nodes after i.n. immunization and i.m. injection. This data provides evidence which supports the long-term immune responses and the basis of further research on safety issues.