Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy

Oral tolerance is a method of downregulating an immune response by feeding antigens. The use of oral tolerance toward adenoviruses and colitis-extracted proteins for long term gene therapy and alleviation of experimental colitis, and the mechanisms of tolerance induction are presented. Adenoviruses...

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Main Author: Yaron Ilan
Format: Article
Language:English
Published: Wiley 1999-01-01
Series:Canadian Journal of Gastroenterology
Online Access:http://dx.doi.org/10.1155/1999/180648
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author Yaron Ilan
author_facet Yaron Ilan
author_sort Yaron Ilan
collection DOAJ
description Oral tolerance is a method of downregulating an immune response by feeding antigens. The use of oral tolerance toward adenoviruses and colitis-extracted proteins for long term gene therapy and alleviation of experimental colitis, and the mechanisms of tolerance induction are presented. Adenoviruses are efficient vectors in liver-directed gene therapy; however, the antiviral immune response precludes the ability to achieve long term gene expression and prohibits the ability to reinject the recombinant virus. Oral tolerance induction via feeding of viral-extracted proteins prevented the antiadenoviral humoral and cellular immune responses, thus enabling long term gene therapy using these viruses. Moreover, pre-existing immune response to the virus was overcome by tolerance induction, enabling prolonged gene expression in a presensitized host. Inflammatory bowel diseases are immune-mediated disorders where an imbalance between proinflammatory (T helper cell type 1) and anti-inflammatory (T helper cell type 2) cytokines are thought to play a role in the pathogenesis. In the experimental colitis model, the feeding of colitis-extracted proteins downregulated the anticolon immune response. Tolerance induction toward colitis-extracted proteins ameliorated colonic inflammation as shown by decreased diarrhea and reduction of colonic ulcerations, intestinal and peritoneal adhesions, wall thickness and edema. Histological parameters for colitis were markedly improved in tolerized animals. In both models, tolerized animals developed an increase in transforming growth factor-beta, interleukin-4 and interleukin-10, and a decrease in the mRNA of interferon-gamma lymphocytes and serum levels. Adoptive transfer of tolerized lymphocytes enabled the transfer of tolerance toward adenoviruses and colon-extracted proteins. Thus, oral tolerance induces suppressor lymphocytes that mediate immune response downregulation by induction of a shift from a proinflammatory T helper cell type 1 to an anti-inflammatory T helper cell type 2 immune response.
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spelling doaj-art-0966b4ff24a64471b3827879f65aeb642025-02-03T07:24:12ZengWileyCanadian Journal of Gastroenterology0835-79001999-01-01131082983510.1155/1999/180648Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene TherapyYaron Ilan0Liver Unit, Division of Medicine, Hadassah University Hospital, Jerusalem, IsraelOral tolerance is a method of downregulating an immune response by feeding antigens. The use of oral tolerance toward adenoviruses and colitis-extracted proteins for long term gene therapy and alleviation of experimental colitis, and the mechanisms of tolerance induction are presented. Adenoviruses are efficient vectors in liver-directed gene therapy; however, the antiviral immune response precludes the ability to achieve long term gene expression and prohibits the ability to reinject the recombinant virus. Oral tolerance induction via feeding of viral-extracted proteins prevented the antiadenoviral humoral and cellular immune responses, thus enabling long term gene therapy using these viruses. Moreover, pre-existing immune response to the virus was overcome by tolerance induction, enabling prolonged gene expression in a presensitized host. Inflammatory bowel diseases are immune-mediated disorders where an imbalance between proinflammatory (T helper cell type 1) and anti-inflammatory (T helper cell type 2) cytokines are thought to play a role in the pathogenesis. In the experimental colitis model, the feeding of colitis-extracted proteins downregulated the anticolon immune response. Tolerance induction toward colitis-extracted proteins ameliorated colonic inflammation as shown by decreased diarrhea and reduction of colonic ulcerations, intestinal and peritoneal adhesions, wall thickness and edema. Histological parameters for colitis were markedly improved in tolerized animals. In both models, tolerized animals developed an increase in transforming growth factor-beta, interleukin-4 and interleukin-10, and a decrease in the mRNA of interferon-gamma lymphocytes and serum levels. Adoptive transfer of tolerized lymphocytes enabled the transfer of tolerance toward adenoviruses and colon-extracted proteins. Thus, oral tolerance induces suppressor lymphocytes that mediate immune response downregulation by induction of a shift from a proinflammatory T helper cell type 1 to an anti-inflammatory T helper cell type 2 immune response.http://dx.doi.org/10.1155/1999/180648
spellingShingle Yaron Ilan
Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy
Canadian Journal of Gastroenterology
title Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy
title_full Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy
title_fullStr Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy
title_full_unstemmed Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy
title_short Oral Tolerance: A New Tool for the Treatment of Gastrointestinal Inflammatory Disorders and Liver-Directed Gene Therapy
title_sort oral tolerance a new tool for the treatment of gastrointestinal inflammatory disorders and liver directed gene therapy
url http://dx.doi.org/10.1155/1999/180648
work_keys_str_mv AT yaronilan oraltoleranceanewtoolforthetreatmentofgastrointestinalinflammatorydisordersandliverdirectedgenetherapy