Evidence of precursors of defective measles virus

Abstract

Cytoplasmic extracts of Vero cells infected with wild strain Edmonston measles virus were found to contain at least two distinct nueleocapsid species. The two most prominent species of nucleocapsids sedimented at 200S and ll0S and contained RNA of molecular weight 6.0 • 10 e and 0.6 • l0 s daltons respectively. Both species of nucleocapsids had a density of 1.31 g/cm 3 in CsC1. A third species sedimenting at 170S was not present in all experiments and was not characterized in detail. Infection of cells with undiluted-passage virus usually resulted in production of mostly ll0S nucleoeapsids while both ll0S and 200S species were found when diluted-passage virus was used. These results suggest that measles virus may produce distinct classes of defective virus which contain segments of RNA representing as little as 10% of the complete viral genome.

Biological and biochemical characterization of a latent subacute sclerosing panencephalitis (SSPE) virus infection in tissue culture

“…Although more than 99% of the TCAprecipitable counts generally remained on the top of the gradient, two distinct peaks of radioactivity were observed. The major peak sedimented at 100-160 S, whereas the minor peak had a sedimentation coefficient of 220-300 S. These peaks contained 91% and 9% of the remaining radioactivity and are considered t o be subgenomic and genomic nucleocapsids, respectively (Hall et al, 1974;Kiley and Payne, 1974). The results are in direct contrast to the situation obtained in Vero cells lytically infected with SSPE (Lec strain) virus (Fig.…”

Effect of Undiluted Passage on the Polypeptides of Measles Virus

“…Undiluted passage of measles virus allows the accumulation of defective interfering (DI) particles (Hall et al 1974;Kiley & Payne, 1974) and these appear to be involved in the establishment of persistent infections of Vero cells by measles virus (Rima & Martin, 1976;Rima et al t 977) and by closely related canine distemper virus (ter Meulen & Martin, 1976 ). To study the mechanism by which DI particles establish persistent infection, we have investigated their effect on polypeptide synthesis in measles infected cells and on the composition of measles virus particles produced during infections which yield a low number of p.f.u./cell.…”

Characterization of the Halle SSPE Measles Virus Isolate

“…However, this heterogeneity has subsequently been shown to exist in several measles isolates as well as in SSPE isolates (Hall et aL, 1979;Rima et al, 1979). The isolation of defective particles containing smaller nucleocapsids and subgenomic RNA from persistently infected cells has also been described (Hall et al, 1974;Kiley & Payne, 1974;Kratzsch et al, 1977).…”