Axenic cultivation of Entamoeba histolytica: progress and problems.

Eighteen years of technological progress in the field of axenic cultivation of Entamoeba histolytica is reviewed. During this period cumbersome diphasic media gave way to easily prepared clear liquid media. Yields of amebae were increased a thousand fold, and doubling time reduced from 24 to less than 8 hours. Attention is directed to three problems, any one of whose solution will extend the potencial of the axenic cultures. They are 1) to develop a defined medium, 2) to reduce the interval between isolation of the amebae from the host and their establishment in axenic culture, thus lessening the opportunity for selection and/or mutation to occur during a period of high risk, 3) to develop a method whereby the entire life cycle of E. histolytica, and not merely cultivation of the trophic form, can be realized under axenic conditions.