Antiviral Immunity in the Fruit Fly, Drosophila melanogaster

Abstract

The fruit fly, Drosophila melanogaster, is an extremely useful model to study innate immunity mechanisms. A fundamental understanding of these mechanisms as they relate to various pathogens has come to light over the past 30 years. The discovery of Toll-like receptors and their recognition of shared molecules (pathogen-associated molecular patterns or PAMPs) among pathogenic bacteria were the first detailed set of receptors to be described that act in innate immunity. The immune deficiency pathway (Imd) described in D. melanogaster functions in a very similar way to the Toll pathway in recognizing PAMPs primarily from Gram-negative bacteria. The discovery of small interfering RNAs (RNAi) provided a means by which antiviral immunity was accomplished in invertebrates. Another related pathway, the JAK/STAT pathway, functions in a similar manner to the interferon pathways described in vertebrates, also providing antiviral defense. Recently, autophagy was also shown to function as a protective pathway against virus infection in D. melanogaster. At least three of these pathways (Imd, JAK/STAT, and RNAi) show signal integration in response to viral infection, demonstrating a coordinated immune response against viral infection. The number of pathways and the integration of them reflect the diversity of pathogens to which innate immune mechanisms must be able to respond. The viral pathogens that infect invertebrates have developed countermeasures to some of these pathways, in particular to RNAi. The evolutionary arms race of pathogen vs. host is ever ongoing.

A Drosophila glial cell atlas reveals a mismatch between transcriptional and morphological diversity

“…We then visualised single glial cell morphology at 0 hours after larval hatching (0h ALH) to assess morphological diversity both within and between classes (Fig 1). Note that in addition to the 5 major glial classes described above, the VNC contains a distinct class called the midline glia, which are a transient population found only during embryonic and larval stages [28][29][30][31]. Although midline glia express wrapper, otherwise known as a cortex glia marker [32][33][34], they do not resemble cortex glia in form or function but instead ensheath commissural axons and play critical roles in axon guidance and VNC morphogenesis [35].…”

Drosophila melanogaster: A Robust Tool to Study Candidate Drug against Epidemic and Pandemic Diseases

“…During the preliminary stage of viral infection Drosophila toll receptor homolog of human TLR, Imd (TNF-alpha), Domeless (Jak-STAT), and RNAi plays a major role against viral infection these are components of innate immune system [45]. Similar to humans the viral glycoproteins are recognized by toll receptors like toll-4, while toll-7 dependent autophagy observed during viral infection in flies [42,46].…”