"Developing a long-term in vitro culturing system for Cryptosporidium parvum"

Cryptosporidium parvum is an intracellular protozoan parasite that belongs to the Apicomplexa phylum and is one of the most common causative agents of cryptosporidiosis, a diarrheal disease. Cryptosporidium infections typically develop due to the consumption of contaminated food or water or direct contact with infected hosts/animals. It causes acute watery diarrhoea and gastrointestinal disease in both immunocompetent and immunocompromised individuals, with symptoms persisting longer in immunocompromised patients due to their weakened immune status. The disease affects both developing and developed countries; however, developing countries are more severely affected by it due to their lower hygienic standards. Even though the disease is considered a major health issue, there are still no effective treatments available. The only FDA-approved drug for the treatment of the disease is Nitazoxanide; however, it is not considered adequate in immunocompromised individuals. The reason for the lck of treatments and vaccines against cryptosporidiosis is the absence of a long-term in vitro culturing system that can support the efficient and long-term propagation of C. parvum. Currently, the HCT-8 cell line can support parasite propagation for a few days, while the COLO680N cell line can support propagation for several weeks. Building on the success of our laboratory with the COLO680N cell line, we tested additional cancer cell lines to assess their effectiveness in maintaining the long-term and efficient propagation of C. parvum, using HCT-8 and COLO680N as guides. From our findings, only four of the ten cancer cell lines that were tested were categorised as optimal (COLO320, SW620, MDA-MB-468, COL680N) since they were able to support long-term propagation of the parasite; however, they were not able to produce a sufficient number of infectious oocysts, which highlights reproducibility issues that other researchers have also faced. Future work aims to pivot to three-dimensional systems, rather than using the monolayer, by supplementing cell lines and maintaining them to enhance long-term propagation, as well as to achieve sufficient oocyst propagation.