Our data clearly show that the WT → LTβ−/− mice produced significant levels of trypanosome-specific class-switched IgG1, IgG2c and IgG3, and this coincided with the ability of the WT → LTβ−/− mice to control further relapses in the parasitemia to a similar extent as WT mice. Here, IGHG3 is linked to parasitic infectious disease.