Drosophila eiger mutants are sensitive to extracellular pathogens.
We showed previously that eiger, the Drosophila tumor necrosis factor homolog, contributes to the pathology induced by infection with Salmonella typhimurium. We were curious whether eiger is always detrimental in the context of infection or if it plays a role in fighting some types of microbes. We challenged wild-type and eiger mutant flies with a collection of facultative intracellular and extracellular pathogens, including a fungus and Gram-positive and Gram-negative bacteria. The response of eiger mutants divided these microbes into two groups: eiger mutants are immunocompromised with respect to extracellular pathogens but show no change or reduced sensitivity to facultative intracellular pathogens. Hence, eiger helps fight infections but also can cause pathology. We propose that eiger activates the cellular immune response of the fly to aid clearance of extracellular pathogens. Intracellular pathogens, which can already defeat professional phagocytes, are unaffected by eiger.
Schneider
David S
DS
Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America. dschneider@stanford.edu
Ayres
Janelle S
JS
Brandt
Stephanie M
SM
Costa
Alexandre
A
Dionne
Marc S
MS
Gordon
Michael D
MD
Mabery
Eric M
EM
Moule
Madeleine G
MG
Pham
Linh N
LN
Shirasu-Hiza
Mimi M
MM
D000818:Animals; D052982:Beauveria / Q000276:immunology / Q000472:pathogenicity*; D016956:Burkholderia cepacia / Q000276:immunology / Q000472:pathogenicity*; D004330:Drosophila / Q000276:immunology / Q000382:microbiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D005786:Gene Expression Regulation; D006094:Gram-Positive Bacteria / Q000276:immunology / Q000472:pathogenicity*; D007113:Immunity, Innate / Q000502:physiology; D016867:Immunocompromised Host / Q000276:immunology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation
D029721:Drosophila Proteins; D008565:Membrane Proteins; C464573:egr protein, Drosophila