Figure 2 Electron microscopy of ultramicroscopic structure changes in 5 cell lines and HPTEC infected with BTV-10 72 hours after infection. HPTECs clearly show an unchanged ultramicroscopic structure compared to the untreated cells: microvilli (MT, arrows), chondriosome (M, arrows), rough endoplasmic reticulum (ER, arrows), nucleus (N) (A ×4000, B ×8000). Viral particles (VP) were observed in all the RCC cell lines, but not in the HPTECs (arrows) (B, C ×8000, D ×13000, G ×6000, H ×12000, K ×6000, L ×15000). Electron microscopy showed chromatin condensation along the periphery of the nucleus (C, E ×4000, G, I ×6000, K), expansion of the rough endoplasmic reticulum (arrows) (I, J ×17 000), decrease of mitochondrial matrix density, and balloon-like swelling (F ×17 000, G, H) in RCC cell lines. (A, B). HPTEC, (C, D). ACHN, (E, F). CAKI-1, (G, H). OR-SC-2, (I, J). 786-0, (K, L). A498.