It is generally stated that our adaptive immune system can differentiate between self and non-self and that it tolerates self (own tissues) and attacks non-self, e.g. an allograft, invading pathogens, etc. However, there are certain situations in which this generalization doesn't hold true. For example, a fetal allograft is tolerated though 'non-self' while a self tissue is targeted in autoimmune disease.
The matter of fact is, our immune system tolerates certain antigens and rejects others and the simple explanation through the self/non-self dichotomy doesn't hold true in all situations. The universal Law of Immunological Tolerance (uLIT) defines the exact criterion used by the Nature for induction of tolerance. It applies to all clinical and experimental scenarios. The Law of Immunological Tolerance states that an activated T cell becomes tolerant to its specific antigen if, and only…
