Francisella is sensitive to insect antimicrobial peptides
2013 (English)In: Journal of Innate Immunity, ISSN 1662-811X, E-ISSN 1662-8128, Vol. 5, no 1, 50-59 p.Article in journal (Refereed) Published
Francisella tularensis causes the zoonotic disease tularemia. Arthropod vectors are important transmission routes for the disease, although it is not known how Francisella survives the efficient arthropod immune response. Here, we used Drosophila melanogaster as a model host for Francisella infections and investigated whether the bacteria are resistant to insect humoral immune responses, in particular to the antimicrobial peptides (AMPs) secreted into the insect hemolymph. Moreover, we asked to which extent such resistance might depend on LPS structure and surface characteristics of the bacteria. We analyzed F. novicida mutant strains in genes, directly or indirectly involved in specific steps of LPS biosynthesis, for virulence in wildtype and Relish E20 immune deficient flies, and tested selected mutants for sensitivity to AMPs in vitro. We demonstrate that Francisella is sensitive to specific fly AMPs, i.e. Attacin, Cecropin, Drosocin and Drosomycin. Furthermore, six bacterial genes, kpsF, manB, lpxF, slt, tolA and pal, were found to be required for resistance to Relish-dependent immune responses, illustrating the importance of structural details of Francisella lipid A and Kdo core for interactions with AMPs. Interestingly, a more negative surface charge and lack of O-antigen did not render mutant bacteria more sensitive to cationic AMPs and attenuated virulence in flies.
Place, publisher, year, edition, pages
Basel: Karger , 2013. Vol. 5, no 1, 50-59 p.
Francisella tularensis, Drosophila melanogaster, Antimicrobial peptides, Lipopolysaccharide, Host-pathogen interactions
Microbiology in the medical area
Research subject Clinical Bacteriology
IdentifiersURN: urn:nbn:se:umu:diva-54412DOI: 10.1159/000342468PubMedID: 23037919OAI: oai:DiVA.org:umu-54412DiVA: diva2:523733
Originally published in thesis in manuscript form.2012-04-262012-04-262016-05-24Bibliographically approved