Helper T-cell subsets in mouse trichuriasis.

The fate of a primary infection with the nematode parasite Trichuris muris varies between different inbred strains of mouse. Most strains are resistant to infection, expelling the parasite before the adult worms develop. However, a few strains are unable to mount a protective immune response and will harbour chronic infections. Mouse trichuriasis thus provides on excellent helminth model in which to dissect the mechanisms of immunity operating during acute versus chronic infection. Here, Kathryn Else and Richard Grencis describe their recent work on the polarization of the helper T-cell response during infection with T. muris giving predominantly T(H)2-type cells in resistant strains of mouse and predominantly T(H)1-type cells in strains of mouse unable to expel the parasite. They also discuss their findings in relation to polarized helper T-cell responses reported for other intestinal nematodes.