Cellular immunity and pathogen strategies in combative interactions involving Drosophila hosts and their endoparasitic wasps

Abstract

Various cellular innate immune responses protect invertebrates from attack by eukaryotic
pathogens. In insects, assessments of the factor(s) causing, or contributing to, pathogen mortality have long considered as toxic components certain molecules associated with enzyme-mediated melanogenesis. In Drosophila hosts, observations that have prompted additional or alternative considerations are those that document either the survival of certain endoparasitic wasps despite melanotic encapsulation, or the destruction of the parasite with no evidence of this type of host response. Investigations of the production of some reactive intermediates of oxygen and nitrogen during infection provide a basis for proposing that these molecules constitute important elements of the immune arsenal of Drosophila. Studies of the target specificity of virulence factors injected by female wasps during infection that suppress the host immune response will likely facilitate identification of the toxic host molecules, and contribute to a more detailed understanding of the cellsignaling pathways that regulate their synthesis.