Killing of Cryptosporidium sporozoites by Lactoferrin

Abstract

Intestinal infection caused by Cryptosporidium is a major contributor to diarrhea morbidity and mortality in young children around the world. Current treatments for children suffering from cryptosporidiosis are suboptimal. Lactoferrin is a glycoprotein found in breast milk. It has showed bacteriostatic and antimicrobial activity in the intestine. However, the effects of lactoferrin on the intestinal parasite Cryptosporidium have not been reported. In this study, we investigated the anticryptosporidial activity of human lactoferrin on different stages of Cryptosporidium. Physiologic concentrations of lactoferrin killed Cryptosporidium parvum sporozoites, but had no significant effect on oocysts viability or parasite intracellular development. Since sporozoites are essential for the infection process, our data reinforce the importance of breastfeeding and point to the potential of lactoferrin as a novel therapeutic agent for cryptosporidiosis.

Figure 1.

Effects of lactoferrin on sporozoites and oocsyst/sporozoites during Cryptosporidium parvum infection. (A) Sporozoites were incubated (or not) with lactoferrin and then used to infect HCT-8 cells, grey bars indicate the average of three experiments, P values were calculated from a t test, error bars indicates standard deviation. (B) Oocyst were added to HCT-8 cells and incubated with excystation media containing (or not) lactoferrin, the bars represent the median of 2 independent experiments conducted by duplicate.

Figure 2.

Fluorescent microscopy (×100) after exposure to lactoferrin. Samples were incubated with complete media alone (A and B) or with complete media supplemented with lactoferrin at 10 mg/mL (C, D, E, and F). White arrows point sporozoites, line scale = 5 µm.