Immunogenetic aspects of the cellular immune response of Drosophila against parasitoids

Host-parasite relationships represent integrating adaptations of considerable complexity involving the host's immune capacity to both recognize and destroy the parasite, and the latter's ability to successfully invade the host and to circumvent its immune response. Compatibility inDrosophila-parasitic wasp (parasitoid) associations has been shown to have a genetic basis, and to be both species and strain specific. Studies using resistant and susceptible strains ofDrosophila melanogaster infected with virulent and avirulent strains of the waspLeptopilina boulardi demonstrate that the success of the host cellular immune response depends on the genetic status of both host and parasitoid. Immunological, physiological, biochemical, and genetic data form the bases of a two-component model proposed here to account for the observed specificity and complexity of two co-evolved adaptations, host nonself recognition and parasitoid virulence.