Maternal infection during pregnancy influences fetal neurodevelopment.
Maternal immune activation due to infection, allergies, or other exposures during pregnancy switches on the activity of a wide array of inflammatory pathways and proinflammatory molecules. These molecules can cross the blood-brain barrier and the placenta, potentially disrupting fetal neurodevelopment and impairing sensory processing abilities later in life. These impairments are often manifested in neuropsychiatric disorders such as autism or schizophrenia. Findings from a recent study suggest that interleukin-15 modulates the effects of a simulated viral infection during pregnancy.
Interleukin 15, a cytokine that is found primarily in immune cells, plays important roles in regulation of the antiviral immune response. IL-15 also participates in the development of natural killer cells, a type of immune cell that is present in large numbers in the uterus during early pregnancy and participates in placental development.
The study investigators injected pregnant normal mice and mice that lacked IL-15 with polyinosinic:polycytidylic (poly I:C), a chemical used in the laboratory setting to simulate a viral infection. Poly I:C interacts with toll-like receptors to elicit an immune response. Other normal and IL-15-deficient mice received saline injections. The investigators tested the animals' offspring in adolescence and adulthood to identify behavioral problems and auditory hypersensitivity. They collected brain tissue samples from a subset of the offspring for examination.
They found that offspring of IL-15-deficient mice that experienced immune activation during pregnancy were more likely to exhibit behavioral problems and auditory hypersensitivity, suggesting that IL-15 plays roles in brain development. They also noted that exposure to poly I:C and IL-15 deficiency independently altered behavioral manifestations in the mice. However, IL-15 deficiency influenced some of the effects of poly I:C exposure.
These findings suggest that IL-15 modulates the effects of maternal immune activation during pregnancy, with potential long-lasting effects on offspring behavior. They also underscore the importance of appropriate vaccination before and during pregnancy to minimized immune activation and its potential harms.
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