Meeting Abstract
The immune system is a host’s main defense against infection, but how a host responds to parasites can vary between the site of infection and more systemic changes in immune phenotype. Host responses may also depend on physiological condition, demography (body condition, age, sex), and coinfection by other parasites. Such sources of variation, inherent in natural populations, can significantly impact the scale and strength of the immune response. Here we characterized how these factors drive variation in the proinflammatory response in wild wood mice, and in turn, how this variation impacts parasite infection dynamics. We longitudinally measured pro-inflammatory cytokine concentrations (TNF-alpha), immune gene expression at the local and systemic within-host scale (spleen and gut lymph nodes), and infection with the gut nematode Heligomosomoides polygyrus and several other coinfecting parasite species. Drug-treating individuals against gut nematodes differentially impacted inflammation in males and females at the systemic scale (spleen), and hosts of different ages varied at the local scale (gut lymph nodes). We also found that reproductively-active mice had lower local inflammation, potentially the result of competition for resources between immunity and reproduction. Measuring parasite infection dynamics of the wider parasite community revealed that variation in pro-inflammatory responses may also impact coinfecting parasites at multiple scales, with potentially significant implications for parasite spread, coinfection prevalence, and how targeted treatments may impact host condition or susceptibility to reinfection.
