WASHINGTON — How your immune system does its job seems to depend more on your environment and the germs you encounter than on your genes, according to new research that put twins to the test to find out.
The immune system adapts throughout life to fight disease, said Stanford University immunologist Mark Davis, who led the work. Although young children’s immunity might be more influenced by what they inherit from mom and dad, the study released Thursday showed genetic influences waned in adulthood.
Davis compared 78 pairs of twins with identical genetic makeups to 27 pairs of fraternal twins, who are no more alike genetically than any other siblings. In three-quarters of the measurements, differences between pairs of twins were more likely due to non-heritable influences — such as previous infections or vaccinations, even nutrition — than genetics, the researchers reported in the journal Cell. Young identical twins had far more immune similarity than old ones.
