Manually dissociated spleens, thymi, and bone marrow from littermate controls (normal) or transgenic mice were individually cultured in 6-well plates with 3 mL of culture medium for 30 hours. After incubation, supernatants were removed and assayed for IFN-γ (in picograms per milliliter) by ELISA. Results represent the mean ± SD of three tissues per group.