Clinical consequences of circulating CD28-negative T cells for solid organ transplantation

CD28 is an important costimulatory molecule expressed on T cells, interacting with CD80 and CD86 on antigen-presenting cells. All naïve T cells express CD28, but memory T cells may become CD28 negative (CD28neg) as a result of repetitive cell divisions, the influence of TNF-alpha, and infection with cytomegalovirus. This results in accumulation of CD28neg T cells, which may constitute >50% of the total circulating T-cell population in the...