Intrachromosomal location of MK5, a foamy type 1 virus.

In a recent description of the morphogenesis of bovine syncytial virus (BSV), we reported the first observations of animal virus particles within the chromosomes of a dividing cell (Dermott, Clarke & Samuels, 1971). We wish here to report a similar finding for mk5 virus, a simian foamy agent, and a member of the same group (Dermott et al. 1971). mk5 virus which had been stored at -70 °C was added to a suspension of HEp2 cells (1 × 106 cells/ml concentration) in Eagles medium + 10% calf serum (growth medium) at a multiplicity of infection of 50 p.f.u./cell. After adsorption for 1 h at 4 °C, cells were treated and cultured as previously reported (Dermott & Samuels, 1973). Samples for electron microscopy were harvested at various time intervals to correspond to growth curve studies, and prepared for electron microscopy as previously reported (Dermott & Samuels, 1973).