The cellular composition of the human immune system is shaped by age and cohabitation
Detailed population level description of the human immune system has recently become achievable. We used a 'systems level' approach to establish a resource of cellular immune profiles of 670 healthy individuals. We report a high level of interindividual variation, with low longitudinal variation, at the level of cellular subset composition of the immune system. Despite the profound effects of antigen exposure on individual antigen specific clones, the cellular subset structure proved highly elastic, with transient vaccination induced changes followed by a return to the individual's unique baseline. Notably, the largest influence on immunological variation identified was cohabitation, with 50% less immunological variation between individuals who share an environment (as parents) than between people in the wider population. These results identify local environmental conditions as a key factor in shaping the human immune system.
Nature Immunology