Spontaneous secretion of interferon gamma and interleukin 4 by human intraepithelial and lamina propria gut lymphocytes.
BACKGROUND
Cytokines secreted by intestinal T lymphocytes probably play a critical role in regulation of the gut associated immune responses.


OBJECTIVE
To quantify interferon gamma (IFN-gamma) and interleukin 4 (IL-4) secreting cells (SC) among human intraepithelial (IEL) and lamina propria (LPL) lymphocytes from the duodenum and right colon in non-pathological situations and in the absence of in vitro stimulation.


METHODS
Duodenal and right colonic biopsy specimens were obtained from patients with no inflammation of the intestinal mucosa.


METHODS
Intraepithelial and lamina propria cell suspensions were assayed for numbers of cells spontaneously secreting IFN-gamma and IL-4 by a two site reverse enzyme linked immunospot technique (ELISPOT).


RESULTS
The relatively high proportion of duodenal lymphocytes spontaneously secreting IFN-gamma (IEL 3.6%; LPL 1.9%) and IL-4 (IEL 1.3%; LPL 0.7%) contrasted with the very low numbers of spontaneously IFN-gamma SC and the absence of spontaneously IL-4 SC among peripheral blood mononuclear cells. In the basal state, both IFN-gamma and IL-4 were mainly produced by CD4+ cells. Within the colon, only 0.2% of IEL and LPL secreted IFN-gamma in the basal state, and 0.1% secreted IL-4.


CONCLUSIONS
Compared with peripheral lymphocytes substantial proportions of intestinal epithelial and lamina propria lymphocytes spontaneously secrete IFN-gamma and/or IL-4. These cytokines are probably involved in the normal homoeostasis of the human intestinal mucosa. Disturbances in their secretion could play a role in the pathogenesis of gastrointestinal diseases.
Carol
M
M
Department of Immunology, Hôpital Erasme, Université Libre de Bruxelles, Belgium.
Lambrechts
A
A
Van Gossum
A
A
Libin
M
M
Goldman
M
M
Mascart-Lemone
F
F
D000328:Adult; D000368:Aged; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003106:Colon / Q000276:immunology*; D004386:Duodenum / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004848:Epithelium / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism*; D007424:Intracellular Fluid / Q000276:immunology; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013601:T-Lymphocytes / Q000378:metabolism*
D015847:Interleukin-4; D007371:Interferon-gamma