In vitro infection of nonendothelial cells by Ehrlichia ruminantium.

The Welgevonden stock of Ehrlichia ruminantium was propagated in eight nonendothelial cell cultures derived from different animal species, both ruminants and nonruminants. The origins of the cells were: bovine fetal testis (BFT), cat ovary (COC), donkey fibroblasts (DFC), sheep fibroblasts (E(2)), horse testis (HTC), lamb fetal testis (LFT), mouse connective tissue (L), and African green monkey kidney (Vero). Four cell culture types (BFT, E(2), LFT and Vero) required supplementation of the medium with cycloheximide for suitable growth of E. ruminantium, whereas the other four (COC, DFC, HTC, and L) did not. Three other stocks of E. ruminantium, Senegal, Ball 3, and Gardel, were also propagated, either in LFT cultures only or in both E(2) and LFT cell cultures. The Welgevonden stock was successfully initiated using E(2) and LFT cell cultures.