The involvement of the spleen during chronic phase of Schistosoma mansoni infection in galectin-3-/- mice.

Schistosoma mansoni synthesizes glycoconjugates which interact with galectin-3, eliciting an intense humoral immune response. Moreover, it was demonstrated that galectin-3 regulates B cell differentiation into plasma cells. Splenomegaly is a hallmark event characterized by polyclonal B cell activation and enhancement of antibody production. Here, we investigated whether galectin-3 interferes with spleen organization and B cell compartment during chronic schistosomiasis, using wild type (WT) and galectin-3-/- mice. In chronically-infected galectin-3-/- mice the histological architecture of the spleen, including white and red pulps, was disturbed with heterogeneous lymphoid follicles, an increased number of plasma cells (CD19-B220-/lowCD138+) and a reduced number of macrophages (CD19-B220-Mac-1+CD138-) and B lymphocytes (CD19+B220+/highCD138-), compared with the WT infected mice. In the absence of galectin-3 there was an increase of annexin-V+PI- cells and a major presence of apoptotic cells in spleen compared with WT infected mice. In spleen of WT infected mice galectin-3 was largely expressed in lymphoid follicles and extrafollicular sites. Thus, we propose that galectin-3 plays a role in splenic architecture, controlling distinct events such as apoptosis, macrophage activity, B cell differentiation and plasmacytogenesis in the course of S. mansoni infection.