CD4 and infection: IL-10 levels are associated with susceptibility to L. donovani infection (14), thus, IL-10 levels were measured in cell supernatants of antigen-stimulated spleen cells and in the serum from CD4+ T cell specific IL-4Rα deficient mice, wild-type control mice and global IL-4Rα−/− mice at days 15, 30, and 56 post-infection.