FasL-induced downregulation of CD28 expression on jurkat cells in vitro is associated with activation of caspases

Authors

  • Shibin Ma,

    1. Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
    Search for more papers by this author
  • Hirotomo Ochi,

    1. Japan Institute for the Control of Aging, Haruoka 723-1, Japan
    Search for more papers by this author
  • Lianxian Cui,

    1. Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
    Search for more papers by this author
  • Wei He

    Corresponding author
    1. Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
      Corresponding author. Tel.: +86-10-65295992; fax: +86-10-65136981 heweiimu@public.bta.net.cn
    Search for more papers by this author

Corresponding author. Tel.: +86-10-65295992; fax: +86-10-65136981 heweiimu@public.bta.net.cn

Abstract

Ligation of CD28, which is present on the majority of CD4+T cells, promotes proliferation and immune responses. However, expression of CD28 declines with aging, and apoptosis may contribute to this decline. We have investigated the molecular mechanism underlying the decrease in CD28 expression in Jurkat T cells cultured with FasL. FasL blocks expression of CD28 at the transcriptional level. This correlates with activation of caspase cascades: active caspase-3 can be detected and inhibitors of caspase-3 and caspase-8 increase CD28 promoter activity and CD28 expression. These findings are consistent with the hypothesis that apoptosis plays a key role in the age-related decline of CD28 expression and hence in immunosenescence.

Ancillary