The reproductive status of the host determines the tolerance and resistance toMycobacterium marinuminfection inDrosophila melanogaster

Abstract

AbstractBoth the sex and the reproductive status of the host have a major impact on the regulation of the immune response against infection. Due thatDrosophila melanogasterhas become a powerful model for study such interactions, we wanted to understand whether the sex or the reproductive status has an impact on the tolerance or resistance of the host to the in the model of systemicMycobacterium marinuminfection. We measured gene expression by RT-qPCR of immune genes,diptericinanddrosomycin, as well as host survival and the bacillary load at time of death. We also assessed the impact of metabolic (by expression ofupd3andimpl2) and hormonal (byecRexpression) regulation in the protection against infection. Data showed that resistance increased in actively mating males and females, and also in mated females while reducing the tolerance to infection. The data also suggest the Toll and IMD pathways determine tolerance and resistance, respectively, while basal levels ofecRfavors the stimulation of the IMD pathway. A time related role has been found forupd3expression, linked to the increase or decrease in the mycobacterial load at the beginning and at the end of the infection, respectively. Finally,impl2expression has been related to the increase of resistance only in non-actively mating males. The results obtained allows further interpretation of the results when assessing the differences between sexes and highlights the role of the reproductive status inD. melanogasterto face infections, since our data demonstrated their importance to determine resistance and tolerance againstM. marinuminfection.