Effects of managanese salts on the AIDS-related pathogen,Cryptosporidium parvum in vitro and in vivo

The authors examined the effects of manganese salts on the interaction of the AIDS-related pathogen,Cryptosporidium parvum, with human ileoadenocarcinoma (HCT-8) cells in vitro. Manganese (Mn) inhibited binding ofC. parvum sporozoite membrane antigens to intact, fixed HCT-8 cells in a dose-dependent fashion, whereas Ca⁺⁺, Mg⁺⁺, and Zn⁺⁺ salts had no effect. Manganese was also found to affect sporozoite penetration of live HCT-8 cells, which resulted in a dose-dependent inhibition of parasite development. However, the levels of Mn⁺⁺ needed in the live cell assays was approx 10-fold greater than in the fixed-cell assays. This inhibition of parasite development was not reversible when Ca⁺⁺ or Mg⁺⁺ were used as competitors. Oral supplementation of suckling mice infected withC. parvum with MnSO₄ resulted in significant reductions and, in some cases, elimination of intestinally derived oocysts.