Immune
Tolerance
It is recognized that, animals do not make antibodies against their own antigens, i.e. they are tolerant to these substances. Injection of foreign antigens into rats or rabbits shortly after birth induces long-lasting tolerance to these antigens. Immune tolerance can also be brought about in adult animals by (i) temporary suppression of the animal's immune system by toxic drugs or irradiation and administration of antigen during this period and (ii) by administration of very high doses of antigens or repeated very low (subimmunogenic) doses.
