Characterization of Chikungunya pseudotyped viruses: Identification of refractory cell lines and demonstration of cellular tropism differences mediated by mutations in E1 glycoprotein.

Chikungunya virus (CHIKV) is an alphavirus responsible for a number of large outbreaks. Here we describe the efficient incorporation of CHIKV envelope glycoproteins into lentiviral and rhabdoviral particles. Vectors pseudotyped with CHIKV envelope proteins efficiently transduced many cell types from different species. However, hematopoietic cell types were either partially or completely refractory. A mutation in E1 (A226V) has been linked with expansion of tropism for mosquito species, although differences in in vitro infection of mosquito cell lines have not been noted. However, pseudovirion infectivity assays detected subtle differences in infection of mosquito cells, suggesting an explanation for the changes in mosquito tropism. The presence of C-type lectins increased CHIKV pseudotyped vector infectivity, but not infection of refractory cells, suggesting that they act as attachment factors rather than primary receptors. CHIKV pseudotypes will serve as an important tool for the study of neutralizing antibodies and the analysis of envelope glycoprotein functions.