[HTML][HTML] Interleukin-4 activated macrophages mediate immunity to filarial helminth infection by sustaining CCR3-dependent eosinophilia

JD Turner, N Pionnier, J Furlong-Silva… - PLoS …, 2018 - journals.plos.org
JD Turner, N Pionnier, J Furlong-Silva, H Sjoberg, S Cross, A Halliday, AF Guimaraes…
PLoS pathogens, 2018journals.plos.org
Eosinophils are effectors in immunity to tissue helminths but also induce allergic
immunopathology. Mechanisms of eosinophilia in non-mucosal tissues during infection
remain unresolved. Here we identify a pivotal function of tissue macrophages (Mϕ) in
eosinophil anti-helminth immunity using a BALB/c mouse intra-peritoneal Brugia malayi
filarial infection model. Eosinophilia, via CC motif chemokine receptor (CCR) 3, was
necessary for immunity as CCR3 and eosinophil impairments rendered mice susceptible to …
Eosinophils are effectors in immunity to tissue helminths but also induce allergic immunopathology. Mechanisms of eosinophilia in non-mucosal tissues during infection remain unresolved. Here we identify a pivotal function of tissue macrophages (Mϕ) in eosinophil anti-helminth immunity using a BALB/c mouse intra-peritoneal Brugia malayi filarial infection model. Eosinophilia, via C-C motif chemokine receptor (CCR)3, was necessary for immunity as CCR3 and eosinophil impairments rendered mice susceptible to chronic filarial infection. Post-infection, peritoneal Mϕ populations proliferated and became alternatively-activated (AAMϕ). Filarial AAMϕ development required adaptive immunity and interleukin-4 receptor-alpha. Depletion of Mϕ prior to infection suppressed eosinophilia and facilitated worm survival. Add back of filarial AAMϕ in Mϕ-depleted mice recapitulated a vigorous eosinophilia. Transfer of filarial AAMϕ into Severe-Combined Immune Deficient mice mediated immunological resistance in an eosinophil-dependent manner. Exogenous IL-4 delivery recapitulated tissue AAMϕ expansions, sustained eosinophilia and mediated immunological resistance in Mϕ-intact SCID mice. Co-culturing Brugia with filarial AAMϕ and/or filarial-recruited eosinophils confirmed eosinophils as the larvicidal cell type. Our data demonstrates that IL-4/IL-4Rα activated AAMϕ orchestrate eosinophil immunity to filarial tissue helminth infection.
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