Mechanisms of Drosophila Immunity - An Innate Immune System at Work

Abstract

Insect immune systems which lack the type of adaptive immunity known in vertebrates rely on several mechanisms including solid barriers against the environment, rapid coagulation of hemolymph after wounding, the formation of aggregates that immobilize and kill foreign invaders, phagocytosis, and the production of antimicrobial peptides. The mode of action and the regulation of the expression of antimicrobial peptides have been studied intensively for more than three decades and are now increasingly well understood. In addition, the characterization of several key molecules involved in other branches of insect immunity has led to a deeper and much more comprehensive understanding of innate immunity in insects. Here we focus on the current status of our view of immunity in the vinegar fly Drosophila melanogaster, the best characterized insect model. We also discuss how evolutionary and ecological forces may have shaped immune responses in Drosophila as compared to other insect species. Finally, several infection models reveal finely-tuned and pathogen-dependent interactions between Drosophila immunity and fly physiology.

Clotting Factors and Eicosanoids Protect against Nematode Infections

“…B Mortality after infection of knock-down (k/d; using the actin driver line) of the lines for secreted PLA 2 (CG14507), a control cross (w1118, crossed with the actin driver line) and the responder line alone. C Infection of control larvae, imd 1 and Bc mutants alone and imd 1 /Bc double mutants reveals an influence of the imd pathway in the absence of melanization. * p !…”

“…Insect hemolymph clotting serves to seal wounds and has been proposed to contribute to preventing migration of microbes past the wound site [1] , similar to other invertebrates [2] . Using proteomics and bioinformatics, we have previously identified a number of candidate clotting factors and studied their function upon wounding and in infection models [3][4][5] .…”

Socialized medicine: Individual and communal disease barriers in honey bees

“…Honey bees and other insects possess four major and interconnected routes for responding to parasite exposure; the Toll, Imd, Jak/STAT, and Jnk pathways (Theopold and Dushay, 2007). These pathways consist of proteins to recognize signals from invading parasites, proteins to modulate and amplify this recognition signal, and effector proteins or metabolites directly involved with parasite inhibition (Lemaitre and Hoffmann, 2007).…”

Coagulation Systems of Invertebrates and Vertebrates and Their Roles in Innate Immunity: The Same Side of Two Coins?

“…An additional important mechanism that has shaped the evolution of clotting factors more than conservation of proteins is the recombination (shuffling) of conserved domains into new proteins [23] . One example here is Drosophila hemolectin, which is exclusively released from hemocytes and is a significant constituent of Drosophila clotting fibers.…”