Maternal type 2 immunity promotes a microchimeric transfer of systemic type 2 immunity to offspring.

During maternity mothers undergo an immune pivot to a type 2 immune phenotype which is independent of any antigen experience. In this study we present this maternal Type 2 immunity as a key enabler of optimal maternally-driven microchimeric transfer of immunity to helminth infection in offspring. To demonstrate that maternal type 2 immunity dictates offspring immunity we nursed wildtype (WT) offspring on WT or IL-4R-/- foster mothers. WT offspring nursed on IL-4Ra-/- mothers acquired a reduced type 2 immune signature compared to WT offspring nursed on WT mothers. This demonstrated maternal IL-4R imprints type 2 immunity in offspring. This increased type 2 immunity in offspring related to a maternal IL-4R dependent increased frequency of maternal microchimeric cells (MMc) being detected in offspring. Higher worm burdens were detected in offspring nursed on IL-4R-/- mothers, demonstrating that an antigen independent promotion of maternal type 2 immunity provides offspring with protective immunity against a helminth infection. To establish the contribution of increased MMc in offspring nursed on WT mothers in the control of infection, we undertook an antibody mediated depletion of MMc cells in WT offspring. This MMc depletion impaired the control of infection and reduced the magnitude of offspring type 2 immune response against a helminth infection. These findings present antigen independent maternal IL-4R driven type 2 immunity during pregnancy as critical for imparting a profound immune influence via MMc on offspring immunity to infection.