Canine IEL inhibit proliferation of mesenteric lymph node T cells. The proliferative response of mesenteric lymph node cells (LN) and IEL from the small bowel of adult Beagle dogs, stimulated with medium control or PMA plus ionomycin and measured by (³H) thymidine incorporation after 48 h (A). Mean values ± SD of n = 5 experiments are shown. (B) Unsorted mesenteric LN or IEL were either cultured alone with medium control or PMA plus ionomycin, or mesenteric lymph node cells were co-cultured with decreasing ratios of IEL. Mean values ± SD of triplicates of typical experiments out of 5 are shown. The same experiment showing sorted IEL and intestinal epithelial cells (EP) as negative controls (C). Mean values ± SD of triplicates of typical experiments are shown. Values (B and C) were normalized to the maximal proliferation of stimulated lymph node cells (100%).