IL10 and infection: Pre-established infection with the helminth Schistosoma mansoni, or pre-treatment of mice with S. mansoni ova significantly attenuates clinical course, reduces incidence and delays onset of EAE in mice, and is associated with decreased IFN-γ, TNF-α, IL-12 and nitric oxide production by splenocytes, as well as increased production of IL-10 and TGF-β (La Flamme et al., 2003; Sewell et al., 2003).