Human schistosomiasis mansoni: Intensity of infection differentially affects the production of interleukin-10, interferon-γ and interleukin-13 by soluble egg antigen or adult worm antigen stimulated cultures

The effect of the intensity of infection (eggs per gram faeces, epg) on the production of inteferon-γ (INF-γ), interleukin (IL)-10 and IL-13 by peripheral blood mononuclear cells (PBMCs) from individuals living in a Schistosoma mansoni -endemic area was evaluated. In vitro stimulation of PBMCs with soluble egg antigen (SEA) resulted in significantly higher secretion levels of IFN-γ in egg-negative individuals compared with those with an intensity of infection of more than 100 epg. In contrast, the egg-positive group produced significantly higher amounts of IL-10. Levels of IL-13 did not differ significantly between egg-positive and egg-negative groups. These findings suggest that IL-10 is an important cytokine in the control of the T helper cell (Th) type 1 responses during human S. mansoni infection, shifting the immune response from Th0 in egg-negative individuals from an endemic area to a Th2 polarization in chronic infected individuals.