Chronic infections and excessive immune responses cause reduced T-cell antigen æ expression |

[Guest guest]

http://www.biomedcentral.com/news/20030922/01

 

Chronic infections impair immune responseChronic infections and excessive immune

responses cause reduced T-cell antigen æ expression | By Tudor Toma

 

 

The T-cell antigen receptor zeta (æ) chain contains signal-transducing motifs,

and its downregulation has been linked with impaired in vitro T-cell function in

cancer and autoimmune and infectious diseases. However, the exact molecular

mechanisms involved are unknown. In the September 21 Nature Immunology,

Noem#237; Bronstein-Sitton and colleagues at the Hebrew University-Hadassah

Medical School show that reduced æ expression is the normal outcome of an

excessive and potentially hazardous immune response (Nature Immunology,

DOI:10.1038/ni975, September 21, 2003).

 

Bronstein-Sitton et al. used an in vivo system that mimics chronic infections by

exposing healthy mice to heat-killed Porphyromonas gingivalis. They observed

that sustained exposure of mice to bacterial antigens was sufficient to induce

T-cell antigen receptor æ chain downregulation and impair T-cell function. In

addition, the authors showed that downregulation of æ correlated with an

impaired in vivo T-cell–mediated immune response—a phenomenon that required

interferon ãand a TH1-dependent immune response.

 

" We propose that æd own-regulation could be one of the mechanisms that 'shuts

off' an inappropriately extreme immune response, thus maintaining balance in the

immune system, " conclude the authors.

Links for this article

E.W. Shores P.E. Love, " TCR zeta chain in T cell development and selection, "

Current Opinion in Immunology, 9:380-389, June 1997.

[PubMed Abstract]

 

N. Bronstein-Sitton et al., " Sustained exposure to bacterial antigen induces

interferon-ã -dependent T cell receptor æ down-regulation and impaired T cell

function, " Nature Immunology, DOI:10.1038/ni975, September 21, 2003.

http://www.nature.com/ni/

 

Hebrew University-Hadassah Medical School

http://www.md.huji.ac.il/

 

 

 

 

 

 

 

NEW WEB MESSAGE BOARDS - JOIN HERE.

Alternative Medicine Message Boards.Info

http://alternative-medicine-message-boards.info

 

 

 

The New with improved product search