Miller J F, Basten A
Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia.
Curr Opin Immunol. 1996 Dec;8(6):815-21. doi: 10.1016/s0952-7915(96)80010-0.
Several mechanisms exist to prevent lymphocytes from reacting against self-antigens. As T cells develop in the thymus and express antigen-specific receptors, those with high-affinity to self-antigens existing within the thymus are deleted. Low-affinity self-reactive T cells and T cells with receptors against antigens not represented intrathymically will mature and join the peripheral T cell pool. They may either ignore self-antigens expressed by tissues unable to activate T cells through a lack of the appropriate costimulator signals, or they may, under certain conditions, be deleted or rendered anergic and unable to respond. Likewise, B cells that express surface Ig receptors with high binding affinity to membrane-bound self-antigens present in the bone marrow will be rescued by receptor editing or will be deleted, whereas those of lower affinity will migrate to the periphery in either an anergic or indifferent state depending on the degree of receptor engagement by antigen. Once there, their ultimate fate is determined by the availability of T cell help.
存在多种机制来防止淋巴细胞对自身抗原产生反应。当T细胞在胸腺中发育并表达抗原特异性受体时，那些对胸腺内存在的自身抗原有高亲和力的T细胞会被清除。低亲和力的自身反应性T细胞以及具有针对胸腺内未呈现抗原的受体的T细胞会成熟并进入外周T细胞库。它们可能会忽略那些因缺乏适当共刺激信号而无法激活T细胞的组织所表达的自身抗原，或者在某些情况下，它们可能会被清除或变得无反应能力且无法做出反应。同样，那些表达与骨髓中存在的膜结合自身抗原有高结合亲和力的表面Ig受体的B细胞，会通过受体编辑得到挽救或被清除，而那些亲和力较低的B细胞则会以无反应或不敏感的状态迁移到外周，这取决于抗原与受体结合的程度。一旦到达外周，它们的最终命运由T细胞辅助的可用性决定。
