Drosophila immune priming to Enterococcus faecalis relies on immune tolerance rather than resistance

• Published in: PLoS pathogens Vol. 19; no. 8; p. e1011567
• Main Authors: Cabrera, Kevin, Hoard, Duncan S, Gibson, Olivia, Martinez, Daniel I, Wunderlich, Zeba
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 11-08-2023; Public Library of Science (PLoS)
• Subjects: Analysis; Bacteria; Bacterial infections; Biology and Life Sciences; Control; Deficient mutant; Drosophila; Drug resistance in microorganisms; Enterococcus faecalis; Fruit flies; Genes; Genetic transcription; Gram-positive bacteria; Health aspects; Hypotheses; Identification and classification; Immune response; Immune system; Immunological tolerance; Infection; Innate immunity; Insects; Medicine and Health Sciences; Ozone; Physiology; Prevention; Priming; Research and Analysis Methods; Streptococcus infections; Survival; Transcription; United States
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1011567

Innate immune priming increases an organism's survival of a second infection after an initial, non-lethal infection. We used Drosophila melanogaster and an insect-derived strain of Enterococcus faecalis to study transcriptional control of priming. In contrast to other pathogens, the enhanced survival in primed animals does not correlate with decreased E. faecalis load. Further analysis shows that primed organisms tolerate, rather than resist infection. Using RNA-seq of immune tissues, we found many genes were upregulated in only primed flies, suggesting a distinct transcriptional program in response to initial and secondary infections. In contrast, few genes continuously express throughout the experiment or more efficiently re-activate upon reinfection. Priming experiments in immune deficient mutants revealed Imd is largely dispensable for responding to a single infection but needed to fully prime. Together, this indicates the fly's innate immune response is plastic-differing in immune strategy, transcriptional program, and pathway use depending on infection history.