Researchers have learnt that a common childhood virus disables the immunity infants naturally receive from breast milk, resulting in an increased risk of developing allergic asthma later in life.
Allergens and biologic molecules that suppress the immune system are transferred from mothers to infants through breastfeeding, which induces protective regulatory T cells in infants. These assist in preventing the immune system from triggering an allergic reaction to antigens such as pollen and dust.
Mice infected with respiratory syncytial virus (RSV) had increased immune cell infiltration in their airways and increased mucus production when challenged with the egg protein. By contrast, uninfected mice potently prevented airway inflammation and other markers of allergic reaction.