Electron microscopic study of respiratory syncitial (RS) virus: A new approach
The respiratory syncytial (RS) virus is included in the Paramyxoviridae family, genus Pneumovirus. In the present study, three strains were compared: human (HRS), bovine (BRS) and caprine (CRS). The ultrastructure of HRS virus has been previously described according to conventional methods of negative staining and ultrathin sectioning (Berthiaume et al., 1974). Recently, bridges between BRS particles in ultrathin sections were noted (Bélanger et al., 1988). Bridges were also observed with CRS (unpublished results). We were interested in studying, by negative staining, what produced these bridges and why they were present on BRS and CRS particles and not on HRS.Human, bovine and caprine RS virus were propagated in ovine kidney (OK) cells. After 5 to 7 days post-infection, when viral titers were at a maximum, supernatants were collected. They were separated in two parts: the first aliquot was used without treatment immediately after collection; the second aliquot was immediately fixed with glutaraldehyde (final concentration of 0,5% (v/v)) and after ten minutes fixation, samples were prepared for electron microscopy.