Morphology of the Warthin-Finkeldey giant cells in monkeys with experimentally induced measles

Measles in non-human primates

It is six decades since the measles vaccine was first introduced, and yet we continue to see frequent outbreaks of this disease occurring all over the world. Many non-human primate (NHP) species, including apes, are susceptible to the measles virus. Spontaneous measles outbreaks have been described in a number of zoos and primate centers worldwide. Research into the spontaneous and experimental infection of laboratory primates with measles represents an invaluable source of information regarding the biology and pathogenesis of this virus and continues to be an irreplaceable and unique tool for testing vaccines and treatments. The purpose of this literature review is to summarize and analyze published data on the circulation of the measles virus among free-living synanthropic and captive primate populations, as well as the results of experiments that have modeled this infection in NHPs.

Cell-cell fusion induced by measles virus amplifies the type I interferon response

Measles virus (MeV) infection is characterized by the formation of multinuclear giant cells (MGC). We report that beta interferon (IFN-beta) production is amplified in vitro by the formation of virus-induced MGC derived from human epithelial cells or mature conventional dendritic cells. Both fusion and IFN-beta response amplification were inhibited in a dose-dependent way by a fusion-inhibitory peptide after MeV infection of epithelial cells. This effect was observed at both low and high multiplicities of infection. While in the absence of virus replication, the cell-cell fusion mediated by MeV H/F glycoproteins did not activate any IFN-alpha/beta production, an amplified IFN-beta response was observed when H/F-induced MGC were infected with a nonfusogenic recombinant chimerical virus. Time lapse microscopy studies revealed that MeV-infected MGC from epithelial cells have a highly dynamic behavior and an unexpected long life span. Following cell-cell fusion, both of the RIG-I and IFN-beta gene deficiencies were trans complemented to induce IFN-beta production. Production of IFN-beta and IFN-alpha was also observed in MeV-infected immature dendritic cells (iDC) and mature dendritic cells (mDC). In contrast to iDC, MeV infection of mDC induced MGC, which produced enhanced amounts of IFN-alpha/beta. The amplification of IFN-beta production was associated with a sustained nuclear localization of IFN regulatory factor 3 (IRF-3) in MeV-induced MGC derived from both epithelial cells and mDC, while the IRF-7 up-regulation was poorly sensitive to the fusion process. Therefore, MeV-induced cell-cell fusion amplifies IFN-alpha/beta production in infected cells, and this indicates that MGC contribute to the antiviral immune response.