The immune system is a wonderful guardian. It protects us from invading microbes and keeps us healthy. But it must be able to distinguish cells of the host itself from foreign invaders. The lack of self-reactivity is called tolerance. Organ transplants from one person to another risk rejection because the immune system sees the transplanted cells as «foreign».  How then does the mother cope with … Seguir leyendo Tolerance and co-existence begin in the womb