Fish Immunology (1+1)

Unit 11 - Immunologic tolerance

11.3. Tolerance to self antigens
Organisms do not mount a strong immune response against its own (self) antigens, a phenomenon called self-tolerance. When the immune system recognizes a self antigen and mounts a strong response against it, autoimmune disease develops. Nonetheless, the immune system has to recognize self-MHC to mount a response against a foreign antigen. Thus, the immune system is under pressure to discriminate between self and non-self antigen to mediate the right response.
Tolerance to tissue and cell antigens can be induced by injection of hemopoietic (stem) cells in new born or severely immunocompromised animals. Also, grafting of thymus from different animal in early induce tolerance in the animal to the cells and tissue of donor animal. Such animals are known as chimeras.