The Caenorhabditis elegans Model of Legionella Infection
Caenorhabditis elegans can serve as a simple genetic host to study interactions between Legionellaceae and their hosts and to examine the contribution of specific gene products to virulence and immunity. C. elegans nematodes have several appealing attributes as a host organism; they are inexpensive, have robust genetic analysis tools, have a simple anatomy yet display a wide range of complex behaviors, and, as invertebrates, do not require animal ethics protocols. Use of C. elegans as a host model complements cell-based models, providing additional support and consistency of the experimental data obtained from multiple models. The C. elegans innate immune system functions similarly to that of the alveolar macrophage including the apoptosis [a.k.a. programmed cell death (PCD)] pathway located within the germline. The digestive tract of C. elegans is a primary interface between the innate immune system and bacterial pathogens. Thus, the C. elegans host model provides an alternative approach to investigate L. pneumophila immunopathogenesis, particularly in the view of the recent discovery of Legionella-containing vacuoles within the gonadal tissues of Legionella-colonized nematodes supporting the plausible evolutionary origin of the strategies employed by L. pneumophila to counteract macrophage cellular responses.
Key wordsCaenorhabditis elegans Nematode Host model Innate immunity Survival assay Bacterial immunopathogenesis Human macrophage
We thank Mathieu Pinette, Jacqueline Hellinga, Alexander Diamandas, and Dr. Jay Kormish for their contributions. This work was supported by a Howard Hughes Medical Institute Early Career Award to C.D.S., and a National Science and Engineering Council Discovery Grant, a Canadian Foundation for Innovation, a Manitoba Medical Service Foundation Award and a Manitoba Health Research Council Establishment Grant to A.K.C.B.
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