Secretion of IL-4 by OVA-Tg cells in primary in vitro cultures depends on exogenous IL-4 from TLI-preconditioned mice.

Highly purified naive OVA-Tg CD4⁺ T cells were cultured for 16 hours with OVA peptide and APCs from untreated BALB/c WT (▴), TLI-preconditioned BALB/c WT (●), or TLI-preconditioned BALB/c IL-4^−/− mice (▪) in IL-4 ELISPOT plates. Figure represents 1 of 2 experiments.