A RAPID, RELIABLE METHOD OF EVALUATING GROWTH AND VIABILITY OF INTRAERYTHROCYTIC PROTOZOAN HEMOPARASITES USING FLUORESCENCE FLOW-CYTOMETRY

Fluorescence flow cytometry was employed to assess the potential of a vital dye, hydroethidine, for use in the detection and monitoring of t he viability of hemoparasites in infected erythrocytes, using Babesia bovis as a model parasite. The studies demonstrated that hydroethidine is taken up by B. bovis and metabolically converted to the DNA bindin g fluorochrome, ethidium. Following uptake of the dye, erythrocytes co ntaining viable parasites were readily distinguished and quantitated. Timed studies with the parasiticidal drug, Ganaseg, showed that it is possible to use the fluorochrome assay to monitor the effects of the d rug on the rale of replication and viability of B. bovis in culture. T he assay provides a rapid method for evaluation of the in vitro effect of drugs on hemoparasites and for analysis of the effect of various c omponents of the immune response, such as lymphokines, monocyte produc ts, antibodies, and effector cells (T, NK, LAK, ADCC) on the growth an d viability of intraerythrocytic parasites.