McCormick A L, Santos-Argumedo L, Thomas M S, Heath A W
Division of Molecular and Genetic Medicine, University of Sheffield Medical School, Sheffield, United Kingdom.
Cell Immunol. 1999 Aug 1;195(2):157-61. doi: 10.1006/cimm.1999.1528.
Binding of CD40 by CD154 expressed on activated T cells is a pivotal event in T cell help to B cells, macrophages, and other antigen-presenting cells. Expression of CD154 by MHC mismatched cells, in contrast to expectations, strongly suppressed alloantibody responses against the cells. This was caused by a failure of priming of antibody responses by the CD154 expressing cells. We hypothesize that this lack of response against CD154 expressing cells may represent a mechanism that has evolved to prevent autoantibody responses being generated against the CD154 antigen itself, as B cells expressing antibody reactive with CD154 would probably escape deletion on binding antigen in the bone marrow due to rescue by the simultaneous ligation of CD40.
活化T细胞上表达的CD154与CD40的结合是T细胞辅助B细胞、巨噬细胞及其他抗原呈递细胞过程中的关键事件。与预期相反，MHC不匹配细胞表达CD154会强烈抑制针对这些细胞的同种抗体反应。这是由于表达CD154的细胞无法启动抗体反应所致。我们推测，对表达CD154的细胞缺乏反应可能代表了一种进化而来的机制，以防止针对CD154抗原自身产生自身抗体反应，因为表达与CD154反应性抗体的B细胞在骨髓中结合抗原时，可能因CD40的同时连接而获救，从而逃避清除。
