Veterinary Immunology and Serology

TOLERANCE 

• A number of mechnisms exist to protect an individual from potentially self-reactive lymphocytes; these are given the general term tolerance. A primary mechanism termed central tolerance deletes T-  or B- cell clones before the cells are allowed to mature if they possess receptors that recognize self antigens with greater affinity.
• Central tolerance occurs in the primary lymphoid organs, bone marrow and thymus. However, there are certain lymphocyte clones which are not deleted in the primary lymphoid organs, there are additional safe guards to limit their activity by the peripheral tolerance, which render lymphocytes inactive in the secondary lymphoid organs.
• Peripheral tolerance can be defined as the inactivation of self reactive T cells or B cells in the periphery, rendering them incapable of responding to self.