Weaning induces an increase in the number of specific cytokine-secreting intestinal lymphocytes in mice

Intestinal immunity differs from systemic immunity in several aspects and i s frequently studied separately. In this work we have analysed the frequenc y of mononuclear cells spontaneously secreting the cytokines IL-2, IL-4, IL -5, IL-6, IL-10, interferon gamma (IFN-gamma) and tumour necrosis factor (T NF-alpha), in Peyer's patches and lamina propria of small intestine in mice by enzyme linked immunosorbent spot (ELISPOT) during 1 month after weaning . We have found a high percentage of spontaneous Th-1 as well as Th, cytoki ne-secreting lymphocytes in both populations, Peyer's patches and lamina pr opria, An increase in the number of the lymphocytes secreting most of the s tudied cytokines, at 1 and 2 weeks after weaning, was also observed, These results suggest that the increase in the number of cytokine secreting lymph ocytes may be one of the potential mechanisms involved in the development o f the intestinal immune system at weaning. (C) 2000 Academic Press.