AN IN-VITRO MODEL OF INFECTION OF HUMAN BILIARY EPITHELIAL-CELLS BY CRYPTOSPORIDIUM-PARVUM

Cryptosporidium parvum infection in the immunosuppressed host is frequ ently complicated by biliary tract involvement, The recent production of human biliary epithelial cell lines was exploited to develop an in vitro model of biliary cryptosporidiosis. Infection with C. parvum ooc ysts was detected by LFA and ELISA and confirmed by transmission elect ron microscopy. Inoculation of monolayers with 10(4) to 5 x 10(5) oocy sts/well resulted in a dose-dependent increase in infection, Time-cour se experiments showed that the number of parasitic stages was maximal at 18-24 h after inoculation, Infection was significantly enhanced by bile at concentrations of 50 and 100 mu g/mL and inhibited by 400 mu g /mL paromomycin. Infection of human biliary cells with C. parvum can b e consistently achieved and monitored by use of IFA or ELISA. This sys tem will be of use in evaluating mechanisms of C. parvum infection and response to therapeutic agents in biliary cryptosporidiosis.