LOS ANGELES — An immune system that ensures survival is one of the earliest gifts from a mother to her child. But sometimes, that gift can be a Trojan horse, sending soldiers that are programmed to attack the body’s own antigens into the fetus, where they interfere with brain development.
The result is maternal autoantibody related autism, which may account for as much as 23 percent of the cases of that spectrum of brain disorders.
Now researchers at the University of California, Davis, believe they have found the targets of these maternal autoantibodies, a potential step in the path toward preventive treatment for women contemplating pregnancy.
The researchers also demonstrated that these human autoantibodies can change the social behavior and brain mass of a close primate cousin, the rhesus monkey, in ways that are parallel to autism’s symptoms in humans.
Though the effects of these immunoglobulin-G compounds on animal and human brains have become more clear in recent years, why they arise in the first place remains a mystery.
“You’re making antibodies to your own proteins, rather than foreign bodies; it’s when the immune system gets it wrong,” said UC Davis immunologist Judy Van de Water, lead author of one of the studies, published Tuesday in the journal Translational Psychiatry. “What causes it in this case we may never know.”
Identifying the targets of these oddly programmed proteins has taken years. Van de Water and her colleagues have struggled to tease out all the identities of these compounds from a range of suspect molecules identified through chemical imaging.
But through a complex series of lock-and-key experiments, the team identified seven fetal antigens that were attacked by the maternal autoantibodies. All but one have been linked with the creation and development of neurons, particularly in the hippocampus. That region, associated with memory and learning, has been tied to autism in numerous studies.