Primary evaluation on tissue distribution and environment biosafety of recombinant expression plasmid of swine IL-4 in mice.

In order to evaluate the biosafety of recombinant pcDNA3.1/IL-4 plasmid before it will be used as a immunological adjuvant,We investigated its tissue distribution and biosafety in mice.Recombinant pcDNA3.1/IL-4 plasmid was inoculated through intramuscular injection,then the animals were slaughtered at the different time points for extracting the gDNA.The tissue distribution and integration of recombinant pcDNA3.1/IL-4 plasmid in mice was analyzed by PCR.The environmental fecal and soil samples in the experimental site were also tested for the presence of plasmid DNA in native bacteria.The results showed that plasmid DNA was only detected in muscle of all mice at 1 d after injection.The fragment of plasmid was amplified from the muscle of one-third mice by PCR at 5 d.The plasmid existed in tissue for no more than 15 days after injection and no integration was detected.The results also demonstrated that the recombinant pcDNA3.1/IL-4 plasmid was not detected in environmental bacteria.Therefore,we concluded that the recombinant pcDNA3.1/IL-4 plasmid is safe to both mice and the surrounding environment.