Breastfeeding is associated with a reduced risk of developing asthma in children. Using a murine model we previously demonstrated that mothers with Th1-type immunity to ovalbumin (OVA) transfer antigen-specific protection from OVA-induced allergic airway disease (AAD) to their offspring. The aim of this study was to evaluate the contribution of breastmilk and maternal B cell immunity from allergic mothers in the vertical transmission of protection from AAD.
This was investigated using an adoptive nursing strategy. Naive offspring were nursed by allergic wild-type or B cell-deficient foster mothers with histories of Th2-type immunity to OVA. Following weaning, offspring were immunized with OVA-Al(OH)3 and challenged with aerosolized OVA to induce AAD.
Offspring nursed by wild-type OVA-immune foster mothers demonstrated lower levels of OVA-specific immunoglobulin E, interleukin-5, and airway eosinophilia than progeny nursed by naive control mothers. In contrast, offspring nursed by B cell-deficient OVA-immune foster mothers had similar parameters of OVAinduced AAD as progeny nursed by naive control mothers.
These data demonstrate the ability of breastmilk from allergic mothers to protect offspring from AAD was dependent on intact maternal B cell immunity. Nursing alone, when done by wild-type mothers with AAD, was sufficient for offspring to acquire the antigen-specific protective factor(s) from breastmilk.