In vitro Model for Cryptosporidium parvum Infection

Background: The in vitro culture system of C. parvum has been investigated using numerous cell lines that support the growth of different stages of the parasite which is less expensive and more convenient for the study of host-parasite interactions than in vivo models. Objective of the study: to evaluate in vitro models of C. parvum and to establish an in vitro culture system for further research studies. Material and Methods: Confluent HT-29 Human Colorectal Adenocarcinoma cell monolayers were infected with 4x105 viable C. parvum oocysts, suspended in 200 l cell culture medium (DMEM). Cells were then incubated for 2 hours at 37°C. Cell monolayers that grow on 13 mm glass coverslips were washed twice with PBS and fixed in methanol for 1 min, stained with 10% Giemsa at different periods (6, 24, 48 and 72 h) and then mounted on glass slides. The parasites were counted, and the obtained data were statistically analyzed. Results: It was found that the HT-29 cell line supports the in vitro cultivation of C. parvum. The maximum numbers of parasites were obtained by 6 h and 24 h post-infection. Only immature stages were observed in the cell line after 6 h of infection. However, there were many immature and mature asexual stages in the cell monolayer 24 and 48 post infection. The maximum numbers of parasites were counted in cell monolayer infected by 4x105 oocysts. Conclusion: It was concluded that the HT-29 cell line supports the in vitro cultivation of C. parvum protozoan parasite.