An identical mechanism governs self-nonself discrimination and effector class regulation

Prevailing immunological dogma dictates self-nonself discrimination, meaning to respond or not, and effector class regulation, meaning choosing the most effective response, are two separate decisions the immune system makes when faced with a new antigen. Representing a cardinal departure from the past, our model instead predicts both self-nonself discrimination and effector class regulation are in fact one and the same process controlled by Foxp3 + regulatory T cells (Tregs) whose antigen-specific repertoire is entirely maintained by commensal microbiota-derived cross-reactive antigens.