University of Nottingham logo University of Nottingham researchers have discovered that expecting mothers produce less aggressive sons having a stronger immune system, if faced with a disease threat during pregnancy.

Apparently, this study is the first of its kind to have revealed the trans-generational effect on immune response based on environmental cues, with maternal perception of disease risk in the immediate environment potentially determining offspring disease resistance and social dominance.

For the study, some pregnant mice were resided next to infected male mice, and some next to a controlled group of non-infected males. The infected male mice were infected with a mild blood parasite, Babesia microti. The male and pregnant female mice were caged in such a way that the female mice could see, smell and hear the infected males. However, contact was avoided between them, so as to avoid the spread of the disease.

Researchers then apparently measured the cause of the “ambient cues” on the pregnant female mice’s physiology and behavior. The adult off-springs social behavior and immune response to various diseases were also studied.

Corticosterone is said to be a stress hormone which is believed to affect the fetal and new-born development. Apparently, blood serum levels of corticosterone is said to have increased two-fold in the pregnant female mice that were caged against the infected male mice, as compared to the pregnant female neighbors of the controlled group of non-infected male mice.

Lead researcher, Dr. Olivia Curno, says that, “It seems that the mothers in our study are priming offspring for the environment they will live in. When the risk of disease is high, improved immunity may outweigh any costs associated with reduced social dominance.”

Evidently, the off-springs of the first group of pregnant mice were significantly lesser aggressive adults as compared to the off-springs of the second group of pregnant mice. Supposedly, all the off-springs were injected with B microti, in an attempt to unveil their immunity strength. The off-springs from the first group of diseased environment pregnant mice, apparently, got over the disease faster than their counterparts.

This research was funded by the Biotechnology and Biological Sciences Research Council.

Their results are published in the Royal Society’s flagship biological research journal, Proceedings of the Royal Society B.