Analyses of frequency of infection, specific infectivity , and prionprotein biosynthesis in scrapie-infected neuroblastoma cell clones
1988
Race, R.E. | Caughey, B. | Graham, K. | Ernst, D. | Chesebro, B.
Scrapie, a spongiform encephalopathy of sheep and goats, is caused by a poorly understood transmissible agent in which no nucleic acid has been conclusively identified. Biochemical characterization of agent derived from animal tissues has not been precise because of the tenacious association of the agent with tissue components. As an approach toward obtaining homogenous preparations ofagent generated in vitro, we cloned scraple-infected neuroblastoma cells. By frequency analysis, nearly every cell in expanded cultures contained scrapie agent.We also analyzed cell-dose infectivity relationships and developed a standard curve which allowed various cultures to be compared. Since a proteinase K (PK)-resistant form of a protein desi gnated prion protein (PrP) has been found in partially purified preparations of scrapie agent from infected animal spleens and brains, we sought to identify this protein in cell cultures. No PK-resistant PrP was found in infected or uninfected cultures, although the PK-sensitive PrP was readily detected. These results suggested that PK-resistant PrP may not be an essential component of the infectious scrapic agent.
显示更多 [+] 显示较少 [-]