Weak bases affect late stages of Mayaro virus replication cycle in vertebrate cells

This paper describes the effect of two weak bases (ammonium chloride and ch loroquine) on the morphogenesis of Mayaro virus. When Mayaro virus-infected TC7 (monkey kidney) cells were treated with these agents it was observed t hat weak bases caused a significant reduction in virus yield. Also, cellula r protein synthesis, which is inhibited by Mayaro virus infection, recovere d to nearly normal levels, However, the synthesis of Mayaro virus proteins was affected. These phenomena were dose-dependent. The process of Mayaro vi rus infection in vertebrate cells is very rapid, Virus precursors are not o bserved in cell cytoplasm and budding through the plasma membrane seems to be the only way of virus release. Electron microscopy of cells infected wit h Mayaro virus and treated with weak bases revealed an accumulation of viru s structures in cell cytoplasm, The study also noted an inhibition of buddi ng through the plasma membrane and the appearance of virus particles inside intracytoplasmic vacuoles. These observations indicate an impairment at th e final stages of the virus replication cycle.