{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:35:54Z","timestamp":1760243754812,"version":"build-2065373602"},"reference-count":40,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2012,8,30]],"date-time":"2012-08-30T00:00:00Z","timestamp":1346284800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.3390\/ijms130910863","type":"journal-article","created":{"date-parts":[[2012,8,30]],"date-time":"2012-08-30T12:12:33Z","timestamp":1346328753000},"page":"10863-10879","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Indoleamine 2,3-Dioxygenase (IDO) Downregulates the Cell Surface Expression of the CD4 Molecule"],"prefix":"10.3390","volume":"13","author":[{"given":"Guanyou","family":"Huang","sequence":"first","affiliation":[{"name":"Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China"},{"name":"Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yaoying","family":"Zeng","sequence":"additional","affiliation":[{"name":"Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peiyan","family":"Liang","sequence":"additional","affiliation":[{"name":"Peking University Shenzhen Graduate School, Shenzhen 518000, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Congrong","family":"Zhou","sequence":"additional","affiliation":[{"name":"Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shuyun","family":"Zhao","sequence":"additional","affiliation":[{"name":"Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiuyan","family":"Huang","sequence":"additional","affiliation":[{"name":"Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lingfei","family":"Wu","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xianhui","family":"He","sequence":"additional","affiliation":[{"name":"Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2012,8,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2516","DOI":"10.1096\/fasebj.5.11.1907934","article-title":"Relationship between interferon-gamma, indoleamine 2,3-dioxygenase, and tryptophan catabolism","volume":"5","author":"Taylor","year":"1991","journal-title":"FASEB J"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.jri.2003.11.002","article-title":"Indoleamine 2,3-dioxygenase (IDO) expression in invasive extravillous trophoblast supports role of the enzyme for materno-fetal tolerance","volume":"61","author":"Rieger","year":"2004","journal-title":"J. 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Virol"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/13\/9\/10863\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:52:06Z","timestamp":1760219526000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/13\/9\/10863"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2012,8,30]]},"references-count":40,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2012,9]]}},"alternative-id":["ijms130910863"],"URL":"https:\/\/doi.org\/10.3390\/ijms130910863","relation":{},"ISSN":["1422-0067"],"issn-type":[{"type":"electronic","value":"1422-0067"}],"subject":[],"published":{"date-parts":[[2012,8,30]]}}}