Table 1.

Deficient induction of IL-4 producers from synovial precursors

	Percentage of cytokine-producing cells
	RAPB				RASF
Addition	IL-2	IL-2 + IFN-γ	IFN-γ	IL-4	IL-2	IL-2 + IFN-γ	IFN-γ	IL-4
Nil	19	24	34	2	4	27	60	0
Anti-IFN-γ	23	25	28	1	7	33	47	0
IL-4	32	23	25	14	5	29	49	0
Anti-IFN-γ + IL-4	41	16	20	23	4	23	54	0

CD45RO⁺, CD4⁺ memory effector T cells were obtained from RA matching peripheral blood and synovial fluid. T cells were cultured for 1 week with OKT3 (0.01 μg/ml) and anti-CD28, as described in Materials and methods. Where indicated, the cultures contained saturating concentrations of anti-IFN-γ antibody and/or IL-4. Afterward, the cells were washed, rested for 2.5 days, and restimulated for 6 h with mitogen to assess intracellular cytokines by flow cytometry; 10⁴ cells were analyzed for each sample. The percentage of cytokine-expressing cells for each sample is shown. Similar results were obtained in at least two independent experiments. No significant difference (P > 0.05) was observed in the percentage of synovial IL-4-producing effector cells in the absence or presence of anti-IFN-γ antibody and/or IL-4.