Research on mice finds immunity can be inherited 

The new study suggests that mice’s experiences in life can change the epigenetic immunity of their offspring

Spotted: A new study in the Journal of Nature Immunology has revealed that mice infected with pathogens could pass on a turbo-boosted immune system to their offspring, with no change to their DNA sequences. The process is believed to take place through epigenetic changes, where genes are turned on or off in the mice’s sperm.

For the study, the team exposed mice to infectious elements like fungi or yeast particles to simulate an infection. After they had recovered, the mice were mated with healthy mice. When the resultant pups were exposed to potential pathogens, they showed a much stronger immune reaction compared to mice with uninfected parents. Moreover, the boosted immunity was also carried forward to the second generation of pups.

These findings challenge accepted theories about genetic inheritance. Under standard thinking, random genetic mutations give some individuals better adaptability to the environment. These advantages are then passed on to the individual’s offspring through their DNA. Over the long term, the species becomes stronger through the natural selection of the individuals who have inherited the most beneficial mutations. These findings, however, suggest that there is a much faster route through which species can become better suited to their environment.  

Epigenetics proposes that chemical ‘tags’ or ‘markers’ are created during the lifetime of a single organism, in response to catalysts such as infection. These tags can then affect how that individual’s genes are ‘expressed’. To use a metaphor, inherited DNA provides the basic architectural drawings for an organism. But in order for this blueprint to be developed into a fully-furnished building, DNA needs to be converted into proteins. Chemical tags can interfere with this process.

Epigenetic tags were previously thought to be completely wiped out in the embryo, meaning that embryos are born with an epigenetic blank slate. But what is particularly novel and exciting about this study, is that the findings suggests that the tags caused by the infection were in fact passed on to the mice pups. However, the third generation of pups did not show a stronger immune response, suggesting an epigenetic expiry date.

“We wanted to test if we could observe the inheritance of some traits to subsequent generations, let’s say independent of natural selection”, said study author Dr. Jorge Dominguez-Andres at Radboud University Nijmegen Centre.

Immunity is a particularly pertinent topic with the COVID-19 pandemic. Innovations spotted by Springwise include a machine-learning platform that can model a person’s immune system, and research showing two antibodies together are better than one.