CD4 and infection: It has been further demonstrated that CD4+ T cells are most effective against larval stages of the parasite and that they act locally at the site of infection, since inhibition of the gut homing receptors β7 and αE integrins and the gut homing ligand MAdCAM-1 completely abrogates the ability of transferred CD4+ T cells to expel infection in SCID mice [24, 25].