Splenic ELISPOTS. Frequency of splenic ELISPOTS secreting (A) IFN-γ, (B) IL-2, and (C) IL-4 in response to EGFP.Tg stimulators in individual mice at 32 weeks after treatment with saline (nonchimeric mice) or busulfan (chimeric mice) before B6-EGFP.Tg BMT. Significant differences of nonchimeric versus chimeric mice are shown for all responses (P < .05 using the Mann-Whitney U test).