Breast milk provides babies with life-long protection against infection, according to a new study.
It was previously thought breastfeeding mums stopped passing on protection to their babies when they began bottle feeding them.
But experts from the University of Birmingham said the transfer of immunity was more long-term when they tested the theory on mice.
They also found protection against disease was driven by the transfer of immune cells and completely independent of the mother’s antibodies.
Published in the journal Science Advances, the study observed baby mice breastfed by their mother who caught a worm infection after becoming pregnant.
They found the infants acquired life-long protection from the worm infection after immune cells was passed on to them through their mother’s milk.
The effect was previously thought to be as a result of antibodies, which are used by the immune system to neutralise bacteria and viruses, in the mother’s proteins being passed on.
Experts say the effect is independent from these antibodies and immunity is actually as a result of transferred immune cells providing protection throughout the body from worm infection.
According to the study, the results suggest that mothers exposed to a globally prevalent source of infection, even if before becoming pregnant, provide long-term immunity to infection in their infants.
Lead author Dr William Horsnell, from the University of Birmingham’s Institute of Microbiology and Infection, the University of Orléans in France and the University of Cape Town in South Africa, said: “Immune transfer from mother to infant via breastfeeding is a very important source of protection from early life infection.
“This is the first demonstration that infection prior to pregnancy can transfer life-long cellular immunity to infants.
“The work shows that exposure to an infection before pregnancy can lead to a mother transferring long term immune benefits to her offspring. This is remarkable and adds a new dimension to our understanding of how a mother can influence our health.”
Co-author Prof Adam Cunningham, of the University of Birmingham and co-director of the BactiVac Network, added: “We are particularly interested in how these findings may help to design maternal vaccine strategies that provide longer-term protection to children.
“This work shows that maternal exposure to an infection can permanently alter offspring immunity. Currently vaccination of mothers to protect infants against infection is very important in boosting protection from infection to newborns, however this protection is considered to be transient.
“Our work shows that, in some cases, this effect can also be permanent. This could lead to the design of new vaccines that will be able to be given to a mother to transfer long-term immunity to her children.”