CD4 and infection: When the infection order was reversed during trickle infection to address the effect of introduction of co-infection with M. bovis BCG into an established helminth-induced TH2 environment (Figure 1B), a significant increase in activated effector T cell (CD4+CD25+Foxp3-) percentages in MLNs of co-infected animals was observed in comparison to T. muris-only infected controls (Figure 5E).