Quantitative Comparison of Infection of Neural Cell and Fibroblast Monolayers by Two Strains of Toxoplasma gondii

Abstract

Disease caused by the coccidian Toxoplasma gondii can be confined to the central nervous system, although the parasite is capable of infecting all organ systems. To determine whether neural cells are differentially susceptible to infection and destruction by T. gondii, infection of neonatal mouse brain monolayers was compared to infection of human fibroblast monolayers under the same conditions with equal inocula of two parasite strains. In preliminary experiments there was no difference in total parasite yield or in plaques per monolayer between rodent and human cells. A standardized inoculum of T. gondii RH strain caused 35.6 ± 6.4 (SD) plaques per well in neural explant monolayers compared to 39.3 ± 12.5 plaques per well in fibroblasts. T. gondii P strain produced 35.6 ± 8.9 infected foci per well in neural cells compared to 32.6 ± 9.3 foci in fibroblasts. Intrinsic properties of neural cells do not appear to cause a higher rate of infection than that in nonneural cells.