Copyright © 1993, American Society for Microbiology Microtubule Inhibitors Block Cryptosporidium parvum

No effective therapy exists for Cryptosporidium parnum, a coccidial protozoan parasite that causes severe diarrhea in patients with AIDS. The role of microtubules in parasite invasion of host cells was investigated by incubating 107 oocysts with a HT 29.74 cell line for 24 h in the presence of microtubule-disrupting drugs. The number of parasites per 1,000 cells was reduced by 77 % (P < 0.001, n = 4) from 182 3 in untreated cells to 42 4 in cells treated with 10-4 M colchicine. Inhibition of C. parvum infection was concentration dependent. Similar results were seen with a second microtubular depolymerization agent, vinblastine. These data suggest that microtubules are important in host cell invasion by C. parvum and may represent targets for development of new therapeutic drugs for treatment of cryptosporidiosis. Cryptosporidium parvum is a coccidial protozoan parasite that causes severe diarrhea in patients with AIDS (8, 18). No antimicrobial therapy to date has been demonstrated to be consistently effective in the treatment of cryptosporidiosis. To identify potential new agents, an in vitro infection model was developed by using a differentiated human enterocyte cell line (1, 7, 9). Infection in this cell line by C. parvum ca