@article{mbs:/content/journal/jgv/10.1099/0022-1317-59-1-57, author = "McKimm-Breschkin, Jennifer L. and Breschkin, Alan M. and Rapp, Fred", title = "Characterization of the Hallé SSPE Measles Virus Isolate", journal= "Journal of General Virology", year = "1982", volume = "59", number = "1", pages = "57-64", doi = "https://doi.org/10.1099/0022-1317-59-1-57", url = "https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-59-1-57", publisher = "Microbiology Society", issn = "1465-2099", type = "Journal Article", keywords = "measles virus isolate", keywords = "persistent infection", keywords = "Hallé SSPE variants", abstract = "SUMMARY The Hallé subacute sclerosing panencephalitis (SSPE) measles virus isolate and its plaque-purified progeny were investigated to determine whether any unusual properties could be associated with its ability to cause persistent infection. Three types of plaque-purified progeny were isolated. One population appeared to be similar in biological and biochemical properties to laboratory-adapted measles virus and had the ability to induce syncytia (syn+). A second population (syn−) plaqued more efficiently at 39 °C than at 33 °C, did not cause normal cell fusion at either temperature, and produced particles that interfered with the replication of other measles virus isolates in vivo and in vitro. This syn− virus was further plaquepurified to eliminate the interfering particles, producing the syn− P2 virus. This virus also plaqued more efficiently at 39 °C than at 33 °C, but caused cell fusion only at 39 °C. Both syn− viruses and the parental virus were significantly less virulent in vivo than the syn+ virus and caused a more prolonged infection. Biochemical analysis showed that the syn− P2 population produced particles that banded at two different densities in potassium tartrate gradients; both densities were less than those of the standard laboratory measles virus and the syn+ virus. Although the syn− P2 virus did not cause cell fusion at 33 °C, [35S]methionine labelling demonstrated that the haemolysin/cell fusion protein was present in syn− P2 virions. The production of interfering particles, the inability to cause cell fusion at 33 °C, and the cold-sensitive nature of the syn− population appear to play a role in the ability of the Hallé SSPE virus to establish persistent infection.", }