CD4 and allergic asthma: Interestingly, although the induction of allergic asthma did not result in an accumulation of the IFN-γ-producing Th1 cells in either strain, we found significantly less of those activated CD4 T cells (secreting IFN-γ) in ova-ova March1−/− compared to ova-ova WT (Figure 3(b)).