Clotting factors and eicosanoids protect against nematode infections
| Authors | |
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| Year of publication | 2010 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Entomopathogenic nematodes (EPNs) of the genera Heterorhabditis are obligate and lethal insect parasites. In recent years they have been used increasingly as biological control agents. Infective juveniles occur free living in the soil and are capable of seeking out hosts and penetrate them through the cuticle or natural orifices. EPNs are symbiotically associated with bacteria of the genera Photorhabdus. The bacterial symbionts are essential to kill the host (within 24-48 hours) and digest host tissues. Drosophila larvae are more resistant to nematode infection than Galleria mellonella, but both can be used as natural infection model. The tripartite model (Drosophila, nematodes, bacteria) was recently established and used to show an immune function for transglutaminase, a conserved clotting factor. In this study we used different Drosophila mutants or RNAi lines with defects in clotting or other branches of the immune system. We demonstrated an immune function during nematode infection for known clotting substrates GP150 and Fondue. Our experiments show that compared to control animals Imd and Bc mutant larvae have similar viability after infection. In contrast double mutants in Imd and Bc show significantly higher mortality suggesting that phenoloxidase cooperates with the Imd pathway during the response to the nematobacterial complex. Furthermore, injection of eicosanoid biosynthesis inhibitors increases susceptibility to nematodes implying the importance of eicosanoids. In conclusion, we show that the Heterorhabditis/Photorhabdus infection model is suitable to identify novel regulators of innate immunity. Our research is supported by grants from the Carl-Tryggers Foundation (U.T.) and Grant Agency of Czech Republic (GA206/09/P470). |
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