Human small intestinal epithelial cells secrete interleukin-7 and differentially express two different interleukin-7 mRNA Transcripts: implications for extrathymic T-cell differentiation

Hum Immunol. 1997 Dec;58(2):83-90. doi: 10.1016/s0198-8859(97)00230-9.


The small intestinal epithelium, composed of epithelial cells (EC) and intraepithelial T lymphocytes, is exposed to numerous ingested antigens. Small intestinal EC may act as accessory and/or antigen presenting cells for intestinal T cells, some of which may mature extrathymically and regulate local immunity and tolerance. Since interleukin-7 (IL-7) plays an essential role in T cell maturation and activation, we examined its expression by human small intestinal EC. IL-7 was detected by ELISA in supernatants from 4 of 4 epithelial layer (EpL) cultures. Using RT-PCR, IL-7 mRNA was detected in 4 EpL studied, and two distinct IL-7 transcripts were identified in 3 of the 4. The ratios of the intensities of the larger to the smaller bands varied amongst individuals. Furthermore, the intensity ratios were higher in whole-thickness intestine and lamina propria preparations than in their corresponding EpL. This is the first report of the expression of two IL-7 transcripts in human intestine and of IL-7 secretion by human small intestinal EpL cells. This supports the hypothesis that small intestinal EC may influence differentiation and/or activation of neighboring T cells. The differential expression of the two transcripts may have important implications for immune regulation in the intestinal epithelium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biopsy
  • Bone Marrow Cells / immunology
  • Caco-2 Cells
  • Cell Differentiation / genetics
  • Cell Differentiation / immunology
  • Cell Line
  • Colon / cytology
  • Colon / immunology
  • Electrophoresis, Agar Gel
  • Enzyme-Linked Immunosorbent Assay
  • Epithelial Cells / immunology*
  • Gene Expression / immunology
  • Humans
  • Interleukin-7 / biosynthesis*
  • Interleukin-7 / genetics*
  • Intestine, Small / cytology
  • Intestine, Small / immunology*
  • Leukocytes, Mononuclear / immunology
  • Polymerase Chain Reaction
  • RNA, Messenger / analysis
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • Transcription, Genetic


  • Interleukin-7
  • RNA, Messenger