Pre-conception maternal helminth infection transfers via nursing long-lasting cellular immunity against helminths to offspring
Maternal immune transfer is the most significant source of protection from early-life infection, but whether maternal transfer of immunity by nursing permanently alters offspring immunity is poorly understood. Here, we identify maternal immune imprinting of offspring nursed by mothers who had a pre-conception helminth infection. Nursing of pups by helminth-exposed mothers transferred protective cellular immunity to these offspring against helminth infection. Enhanced control of infection was not dependent on maternal antibody. Protection associated with systemic development of protective type 2 immunity in T helper 2 (TH2) impaired IL-4Rα−/− offspring. This maternally acquired immunity was maintained into maturity and required transfer (via nursing) to the offspring of maternally derived TH2-competent CD4 T cells. Our data therefore reveal that maternal exposure to a globally prevalent source of infection before pregnancy provides long-term nursing-acquired immune benefits to offspring mediated by maternally derived pathogen-experienced lymphocytes.
Maternal transfer of immunity both in utero and via nursing provides critical sources of early-life immune education and protection from disease. Maternally acquired protection from infection is typically associated with a passive transfer to offspring of maternal innate opsonins and antibody, which provide a transient, but critical, early-life ability to counter pathogens (1, 2).
Nursing alone provides important protection to offspring against both infectious and noninfectious diseases (3, 4). While this protection is associated primarily with transfer of maternally derived antibody (5), other immunogenic components of breast milk such as cytokines and antigen can also influence offspring immunity (6). Epidemiological and experimental evidence indicates that maternal immune transfer via nursing may also provide long-lasting pathogen-specific protection from infection, despite the short half-life of substances transferred via breast milk (7, 8). However, the