Indoleamine 2,3-Dioxygenase (IDO) Downregulates the Cell Surface Expression of the CD4 Molecule

International Journal of Molecular Sciences

Guanyou Huang¹  Yaoying Zeng⁴  Peiyan Liang²  Congrong Zhou¹  Shuyun Zhao¹  Xiuyan Huang⁴  Lingfei Wu³ 

[1] Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China; E-Mails:;Peking University Shenzhen Graduate School, Shenzhen 518000, China; E-Mail:;Department of Gastroenterology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China; E-Mail:;Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China; E-Mails:

关键词: human IDO;    CD4;    T cell;    immune tolerance;    immune response;   

DOI  :  10.3390/ijms130910863

来源: mdpi

【 摘 要 】

Indoleamine 2,3-dioxygenase (IDO) has been implicated in preventing the fetus from undergoing maternal T cell-mediated immune responses, yet the mechanism underlying these kinds of IDO-mediated immune responses has not been fully elucidated. Since the CD4 molecule plays a central role in the onset and regulation of antigen-specific immune responses, and T cell is sensitive in the absence of tryptophan, we hypothesize that IDO may reduce cell surface CD4 expression. To test this hypothesis, an adenoviral vector-based construct IDO-EGFP was generated and the effect of IDO-EGFP on CD4 expression was determined on recombinant adenoviral infected C8166 and MT-2 cells, by flow cytometry and/or Western blot analysis. The results revealed a significant downregulation of cell membrane CD4 in pAd-IDOEGFP infected cells when compared to that of mock-infected cells or infection with empty vector pAd-EGFP. Further experiments disclosed that either an addition of tryptophan or IDO inhibitor could partly restore CD4 expression in pAd-IDOEGFP infected C8166 cells. Our findings suggest that downregulation of CD4 by IDO might be one of the mechanisms through which IDO regulates T cell-mediated immune responses.

【 授权许可】

CC BY   
© 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.