Table 1. Percent of total CD4⁺ MLN lymphocytes expressing cell surface activation markers.

Activation Marker	wt TNF+/+ MLN	TNFΔARE/+ MLN	TNFiΔARE/ iΔARE MLN	TNFiΔARE/ iΔARE LP
		(P-value vs. wt)	(P-value vs. wt)	(P-value vs. wt)
CD69+	14.32 ± 1.67	32.05 ± 5.63	33.74 ± 1.54	74.70 ± 1.70
		(0.043)	(0.021)	(0.021)
CD62L-	11.19 ± 0.93	28.18 ± 4.11	37.17 ± 0.44	92.13 ± 0.85
		(0.021)	(0.021)	(0.021)
CD25+	11.57 ± 0.70	29.66 ± 2.41	25.04 ± 1.22	48.72 ± 0.96
		(0.021)	(0.021)	(0.021)

Immunophenotypic characterization of mucosal lymphocytes from TNF^{i∆ARE/i∆ARE} mice with ileitis. Single cell suspensions were obtained from MLNs and small intestinal LP. The expression of various surface markers was analyzed by flow cytometry. Fluorochrome-tagged monoclonal antibodies against CD4, CD69, CD25, and CD62L were utilized for identification of the respective populations. Multiple color flow cytometry was performed on a FACS calibur system to determine the percentage of cells expressing surface markers and the intensity of expression. A significant increase was observed in the proportion of mucosal (MLN and LP) CD4⁺ cells that expressed various markers of activation. The percentages of CD4⁺ cells expressing CD69 or CD25, or lacking expression of CD62L, were significantly elevated in the MLNs of TNF^{i∆ARE/i∆ARE} mice in comparison to wt controls (P<0.05), whereas no differences were seen between intestinal TNF^{i∆ARE/i∆ARE} and systemic TNF^ΔARE/+ mice. The largest percentages of CD4⁺ lymphocytes expressing markers of activation were detected in freshly isolate LP mononuclear cells from TNF^{i∆ARE/i∆ARE} mice. Mice were processed individually. Three separate experiments with 4 mice per group gave similar results. Data are represented as mean values ± SEM for each group of mice.