Development of dual reporter imaging system for <i>Francisella tularensis</i> to monitor the spatio-temporal pathogenesis and vaccine efficacy

다국어 초록 (Multilingual Abstract)

<P><B>Purpose</B></P><P>Study on the pathogen and the pathogen-related disease require the information at both cellular and organism level. However, lack of appropriate high-quality antibodies and the difference between the experimental animal models make it difficult to analyze <I>in vivo</I> mechanism of pathogen-related diseases. For more reliable research on the infection and immune-response of pathogen-related diseases, accurate analysis is essential to provide spatiotemporal information of pathogens and immune activity to avoid false-positive or mis-interpretations. In this regards, we have developed a method for tracking <I>Francisella tularensis</I> in the animal model without using the specific antibodies for the <I>F. tularensis</I>.</P><P><B>Materials and Methods</B></P><P>A dual reporter plasmid using GFP-Lux with putative bacterioferritin promoter (pBfr) was constructed and transformed to <I>F. tularensis</I> live vaccine strain to generate <I>F. tularensis</I> LVS (<I>Ft</I>LVS)-GFP-Lux for both fluorescence and bioluminescence imaging. For vaccination to <I>F. tularensis</I> infection, <I>Ft</I>LVS and lipopolysaccharide (LPS) from <I>Ft</I>LVS were used.</P><P><B>Results</B></P><P>We visualized the bacterial replication of <I>F. tularensis</I> in the cells using fluorescence and bioluminescence imaging, and traced the spatio-temporal process of <I>F. tularensis</I> pathogenesis in mice. Vaccination with LPS purified from <I>Ft</I>LVS greatly reduced the bacterial replication of <I>Ft</I>LVS in animal model, and the effect of vaccination was also successfully monitored with <I>in vivo</I> imaging.</P><P><B>Conclusion</B></P><P>We successfully established dual reporter labeled <I>F. tularensis</I> for cellular and whole body imaging. Our simple and integrated imaging analysis system would provide useful information for <I>in vivo</I> analysis of <I>F. tularensis</I> infection as well as <I>in vitro</I> experiments, which have not been fully explained yet with various technical problems.</P>