Expression of cathepsins B, L, S, and D by gastric epithelial cells implicates them as antigen presenting cells in local immune responses

Carlos Barrera, Gang Ye, Rosario Espejo, Shani Gunasena, Ruben Almanza, James Leary, Sheila Crowe, Peter Ernst, Victor E. Reyes

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39 Scopus citations

Abstract

Helicobacter pylori infection is linked to chronic gastritis, peptic ulcer and gastric carcinoma. During H. pylori infection, class II MHC expression by the gastric epithelium increases, as does the number of local CD4+ T cells, which appear to be important in the associated pathogenesis. These observations suggested that the epithelium might present antigens to T cells. Thus, we sought to determine whether gastric epithelial cells process antigens to establish their function as local antigen presenting cells (APC). We examined a panel of gastric epithelial cell lines for expression of the antigen processing cathepsins B (CB), L (CL), S (CS), and D (CD). The mRNA for these enzymes were detected by RT-PCR and the enzymes in the gastric epithelial cells were identified by various independent methods. We corroborated the expression of CB and CD on gastric epithelial cells from human biopsy samples. The functions of these proteases were confirmed by assessing their ability to digest ovalbumin, a conventional dietary antigen, and proteins from H. pylori. In summary, multiple lines of evidence suggest gastric epithelial cells process antigens for presentation to CD4+ T cells. To our knowledge, these are the first studies to document the antigen processing capacity of human gastric epithelial cells.

Original languageEnglish (US)
Pages (from-to)1081-1091
Number of pages11
JournalHuman Immunology
Volume62
Issue number10
DOIs
StatePublished - Jan 1 2001

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Keywords

  • Antigen presentation
  • Endosomal proteases
  • Helicobacter pylori
  • Mucosal immunity

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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