Cultivation of Cryptosporidium pawum in a non-adherent human monocytic cell line

International audienceCryptosporidium parvum is a coccidian parasite responsible for severe diarrhea in immunocompromised patients. At present, only therapies of limited efficacies are available and despite recent improvements, an easy to perform and reproducible in vitro model is still lacking. The present study shows that the human monocyte cell line THP-1 supports the growth of C. parvum. After inoculation with oocysts, all the asexual and sexual developmental stages were found. Immunofluorescence controls showed that few oocysts remained after infection, disappeared within the first 24 h and that sexual stages reappeared after the second day postinoculation. A continuous asexual life-cycle proceeded throughout the experiments, with at least E-day cultures. Ultrastructural studies evidenced that the parasites were usually localized at the cell surface and also in the cytoplasm, a feature found in vivo with M cells and macrophages. This culture system is easy to initiate and to maintain with adjustable parasitemias and duration which will allow time-dependent drug-testing and also facilitate the study of the biology of this parasite