Recombinant IsSMase programs CD4 T cells responding to associated soluble antigen to develop the capacity to express IL-4. Adoptively transferred CFSE-labeled BALB/c HA-specific TCR transgenic CD4 T cells were recovered following adoptive transfer into BALB/c recipients that were simultaneously treated intradermally with soluble HA peptide and either SGE, IsSMase or PBS (Control or C). A, Representative CFSE-dilution histograms (left side, with the percentage of TCR transgenic CD4 T cells that have diluted CFSE-fluorescence shown) and B, quantitative data (mean ± SEM) corresponding to panel A. C, Representative IFN-γ vs IL-4 intracellular staining plots corresponding to the CFSE-divided TCR transgenic CD4 T cells in panel A. D, Quantitative analysis of intracellular IL-4 expression. N=4 to 6 for each group.