Friends, the concept of Self and Nonself is an important and useful concept in Immunology. We say that Self-antigens are tolerated while Nonself is rejected. However, this concept fails in certain clinical situations. In autoimmunity and in neoplastic disease our own (Self) cells are attacked by our own immune system even though the genotype and MHC are exactly the same. On the other hand, Nonself antigens are tolerated in the case of fetal allograft and in Neonatal acquired immunity, irrespective of the genotype and MHC match/mismatch.
Note that a fetal allograft survives not only in its biological mother but in a surrogate mother too. Friends, do you know why this concept of 'Self' fails us? It is because this 'Self' doesn't denote our body as a whole, but the 'self' is related to the T cell repertoire as they are trained to tolerate 'self-antigens'. Please note that the body's…
