Antigens characteristic of an organ or tissues are called organ-specific antigens. These antigens found in the brain, kidney, and lens tissues, even of different animal species, share the same antigen specificity. Organ-specific antigens, such as brain-specific antigens, shared by human and sheep brain are one such example. The antirabies vaccines prepared from sheep brain, when given, may induce immune response in some humans, causing damage to neural tissues of the recipient. This may result in neuroparalytic complications in some individuals.