|Budget Amount *help
¥2,700,000 (Direct Cost : ¥2,700,000)
Fiscal Year 1996 : ¥2,700,000 (Direct Cost : ¥2,700,000)
The purpose of this study was to establish an in vitro screening system that enables us to search for potent anti-Trypanosoma cruzi agents. We have succeeded in establishing an in vitro culture system using mammalian host cells (HeLa) infected with T.cruzi in which the time course of parasite growth is determined quantitatively. We adopted this system for the screening of anti-T.cruzi agents that would ideally prove to be effective against trypanosomes with no toxicity to the host cell. Of the purine analogs tested, allopurinol markedly inhibited the growth of amastigotes in a dose-dependent manner, with no lethal effect on trypomastigotes. 3'-Deoxyinosine and 3'-deoxyadenosine also suppressed T.cruzi growth inside the host cell, with IC_<50> values of 10 and 5 muM,respectively, in contrast to the value of 3 muM for allopurinol. Among pyrimidine analogs examined, 3'-azido-3'-deoxythymidine (AZT) significantly reduced the growth of the parasite at concentrations as low as 1 muM.The anti-HIV agents, 2', 3'-dideoxyinosine and 2', 3'-dideoxy adenosine, caused a decrease in amastigote growth, while 2', 3', -dideoxycytidine and 2', 3'-dideoxyuridine had no inhibitory effect. These results indicate that our culture system is useful as a primary screening method for candidate compounds against T.cruzi on the basis of two criteria, intracellular replication by the parasite and host-cell infection rate. Using this system, efficacies of calcium channel blockers, synthetic peptides, and natural planta components of Asian origen were also determined.