engleski

Specificity of oral immune priming in Tribolium castaneum

Introduction: In many invertebrate species, enhanced survival of infection has been observed after prior exposure to the same pathogen ('immune priming'). In insects, oral infection is assumed to be the natural route of infection with the spore-forming bacterium Bacillus thuringiensis. The major virulence factors of B. thuringiensis are the plasmid-encoded Cry toxins that are toxic upon ingestion and characterised by high insecticidal specificity. Objectives: While priming via septic wounding in the red flour beetle Tribolium castaneum shows a high level of specificity, it is unclear whether the same phenomenon can also be observed via oral immune priming. Thus, we investigated in our study whether T. castaneum is able to mount an immune priming response to three different strains of B. thuringiensis that are known for their entomopathogenic activity. Materials and Methods: We conducted a full factorial experiment by using our well-established high throughput method for oral infections of individualised larvae. Results: We demonstrate that immune priming can be triggered by oral uptake of the spore supernatant in two of the three bacterial strains. Furthermore, the results point to a certain level of specificity towards two of the strains. Conclusions: We are currently exploring whether the priming response to the third strain might be dependent on the spore dose. However, our results suggest that specificity towards B. thuringiensis is also present in oral priming.

immune memory, Bacillus thuringiensis, Tribolium castaneum

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