Mem Inst Oswaldo Cruz, Rio de Janeiro, VOLUME 114 | NOVEMBER 2019
Skeletal muscle cells of chicken embryos generating the Yellow Fever vaccine virus [ACCEPTED ARTICLES / PRELIMINARY VERSION]
1 Laboratório de Patologia, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro RJ, Brasil
2 Laboratório de Biologia Molecular de Flavivirus, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro RJ, Brasil
The yellow fever vaccine is produced by inoculation of the YF17DD virus in embryonated chicken eggs on the ninth day of development. Full embryos are collected on the twelfth day of development for vaccine formulation. The skeletal muscle tissue is the main site where biosynthesis of viral particles occurs, thus displaying a myoblast-like morphology when first cells are infected. The present work phenotypically characterizes these cells as myogenic precursors expressing the Pax7 transcription factor in some cases. We demonstrate that skeletal chicken embryo muscle cells are susceptible to in vitro infection in different MOI´s thus reproducing the same infection pattern observed in vivo. Furthermore, myogenic precursors and myoblasts are preferred infection targets, but settlement of infection does not depend on the presence of these cells. The peak of viral production occurs in 48 hpi, with decay occurring in 72 hpi, when the cytopathic effect can be observed. These findings allow us to conclude that the primary culture of chicken skeletal muscle cells is a good model for studying muscle cells infected with YF17DD virus, due to its satisfactory emulation of the in vitro phenomenon observed thus contributing to understand virus infection dynamics and leading to the development of alternative methods of vaccine production.