How vertically transmitted gut microbes and immune genes synergistically direct anti-malarial defence in birds

Objective

Mounting an appropriate and effective immune response is critical to protect an organism from infection. In vertebrates, the adaptive immune system (AIS) plays a central role in immunity, and evidence is accumulating that its development is governed by intricate crosstalk between host immune genes and gut bacteria (GB). This implies that specific synergisms exist between bacterial taxa and AIS, mainly encoded by the highly polymorphic Major Histocompatibility Complex genes (MHCs), to promote optimal immunity. However, the specific associations between GB and MHCs in defence against parasites and their potential effects across generations are poorly resolved in one of the largest vertebrate classes: the birds. BornThisWay will close major gaps in our current understanding of immune consequences of GB-MHC crosstalk in wild birds using two ideal study populations. The action will capitalise on my and my host’s (Prof. Helena Westerdahl) extensive backgrounds in avian gut microbiomes and avian adaptive immunity, respectively. BornThisWay will i) establish how GB and MHC act in concert to defend against avian malaria parasites, ii) determine if synergistically optimal protection is transferred across generations, and iii) test immune consequences of GB-MHC crosstalk disruptions. BornThisWay will add a new dimension to host-pathogen interactions in wild birds, generate novel fundamental insights into the adaptive significance of GB-MHC crosstalk, and provide transformative insights of conceptual and empirical value to transgenerational immunity in vertebrates.