A large effort has been made recently to describe viral
tropism and replication in cell culture systems and in
animal models to better understand CHIKV pathogenesis
(for details on the Alphavirus life cycle in mammalian
cells, see BOX 2). Studies in the 1960–1980s showed
that CHIKV grows in a panel of non-human cell lines,
including Vero cells, chick embryo cells, BHK21 and
L929 fibroblast-like cells, and HEp-2 hepatic cells47–50.
The cellular tropism of CHIKV in humans was characterized
recently. In tissue culture experiments, the
virus replicates in various human adherent cells, such
as epithelial and endothelial primary cells and cell lines,
fibroblasts and, to a lesser extent, monocyte-derived
macrophages51. CHIKV also replicates in human muscle
satellite cells, but not in differentiated myotubes52 (FIG. 2).
In contrast to adherent cells, B cells and T cells are not
susceptible to CHIKV infection in vitro51,53. Like other
alphaviruses, CHIKV is highly cytopathic in human
cell cultures, and infected cells rapidly undergo apoptotic
cell death33,51. This pattern of replication probably
governs the pathological properties of the virus