38th Annual Meeting of the Society for Invertebrate Pathology

The innate immune system of Drosophila has both humoral and cellular aspects. Many of the key players involved in the humoral response have been identified in genetic screens and microarray analyses (reviewed in Govind and Nehm, 2004). However, far less is known at the molecular level about the cellular immune response. The cellular response involves phagocytosis or encapsulation of pathogens by hemocytes (blood cells). The latter response can be triggered by parasitic wasp infestation. In order to get a better understanding of the transcriptome underlying an antiparasitic immune response, a timecourse microarray analysis has been performed following infestation of larvae by Leptopilina boulardi, a natural parasite of Drosophila. The infestation-dependent genes that have been identified contribute to several biological processes including immune and stress responses. Similar to the bacterial immune response, a large proportion of the transcripts identified are serine proteases. Interestingly, the majority of these proteases have not been previously associated with an immune response, indicating that the induction of the response may be fundamentally different from other immune challenges.