246B Poster - 02. Immunity and the microbiome
Friday April 08, 2:00 PM - 4:00 PM

Authors:
Radhika R ¹; Brian Lazzaro ^1,2

Affiliations:
1) Cornell University; 2) Cornell Institute of Host-Microbe Interactions and Disease (CIHMID)

Keywords:
e. anti-microbial peptides; b. transcription initiation/elongation/termination

Production of Anti-Microbial Peptides (AMP) is an integral part of the anti-bacterial infection response in insects. Controlled primarily by the Toll and Imd signaling pathways, a wide array of AMP genes are upregulated within four to six hours of hosts encountering bacterial pathogens. A model of infection progression developed by Duneau et al. 2017 suggests that this early phase of infection response, lasting up to about twelve hours, is very important for effective pathogen control. Hosts that survive infection do so by restricting pathogen load to a low, sustained residual burden that they retain for the rest of their life, while those that allow pathogens to grow unchecked succumb to infection. In this study, using Drosophila melanogaster as our model system, we test whether differences in AMP induction kinetics in the early phase of infection predict how well hosts curtail pathogen growth and thereby survive infections. Our hypothesis is that faster upregulation of the AMP(s) will correlate with increased probability of host survival and lower residual bacterial loads among surviving hosts. We first systematically tested which AMP(s) are the most important for controlling infection by each of four different bacteria using a panel of mutants that are deficient for different combinations of AMP genes. We then measured ten lines from the Drosophila Genome Reference Panel (DGRP) for their ability to survive infection with the four bacteria. In ongoing studies, we are testing whether the kinetics of AMP upregulation predict the probability of host survival of infection, specifically predicting that the strongest correlation will be seen with the expression of AMPs that are disproportionately important for controlling an infection by a given bacteria while other co-regulated AMPs may correlate more weakly. If the data support this hypothesis, that would provide key evidence that the rapid induction of AMP gene expression is essential for control of infection.