Enhanced function of IVIg-expanded Treg. (A) C57BL/6J mice (4 per group) were reconstituted (●) or not (▴) with 0.25 million Treg from IVIg-treated mice or (○) untreated mice. After 24 hours, recipient mice were subjected to an EAE induction. Data are the means plus or minus SD (*P < .05). (B) Suppression by IVIg-expanded Treg in vitro: 5 × 10⁴ CD4⁺CD25⁻ cells isolated from the splenocytes of diseased mice were stimulated to proliferate for 96 hours with or without various concentrations of CD4⁺CD25⁺ cells isolated from the splenocytes of IVIg-treated (□) or PBS-treated (■) mice cells in round-bottom 96-well plates coated with anti-CD3 Abs and with soluble anti-CD28 Abs (1 μg/mL). Consistent data were obtained in 2 independent experiments.