IL13 and infection: T-bet/IFN-γ co-expressing cells were detected in similar proportions within IL-4 and IL-13 producers from spleens of mice infected for 10 days (Figure 3F) and the frequencies of IFN-γ+ Th2/1 hybrids in Th2 cytokine producing populations were similar when comparing day 10 and 20 post infection (Figure 3G).