%0 Journal Article
%1 Haid30122015
%A Haid, S
%A Grethe, C
%A Bankwitz, D
%A Grunwald, T
%A Pietschmann, T
%D 2015
%E Virol, J
%J J Virol
%K pietschmann
%N 6
%P 3065-3073
%T Identification of a human respiratory syncytial virus (hRSV) cell entry inhibitor by using a novel lentiviral pseudotype (hRSVpp) system
%V 90
%X Lentiviral budding is governed by Group-specific antigen (Gag-proteins) and proceeds in the absence of cognate viral envelope proteins, which has been exploited to create pseudotypes incorporating envelope proteins from non-lentiviral families. Here, we report the generation of infectious lentiviral pseudo-particles incorporating human respiratory syncytial virus F protein alone (hRSV-Fpp) or carrying SH, G and F proteins (hRSV-SH/G/Fpp). These particles recapitulate key infection steps of authentic hRSV particles including utilization of glycosaminoglycans and low pH independent cell entry. Moreover, hRSVpp can faithfully reproduce phenotypic resistance to a small molecule fusion inhibitor in clinical development (BMS-433771) and a licensed therapeutic F protein targeting antibody (palivizumab). Inoculation of several human cell lines from lung and liver revealed more than 30-fold differences in susceptibility to hRSVpp infection, suggesting differential expression of hRSV entry co-factors and/or restriction factors between these cell types. Moreover, we observed functional differences between hRSVpp carrying solely F protein or SH, G and F proteins with regard to utilization of glycosaminoglycans in a cell type-dependent manner. Using hRSVpp we identified penta-O-galloyl-β-D-glucose (PGG) as a novel hRSV cell entry inhibitor. Moreover, we show that PGG also inhibits cell entry of hRSVpp carrying F-proteins resistant to BMS-433771 or palivizumab. This work sheds new light onto the mechanisms of hRSV cell entry including possible strategies for antiviral intervention. Moreover, hRSVpp should prove valuable to dissect hRSV envelope protein functions including the interaction with cell entry factors.IMPORTANCE Lentiviral pseudotypes are highly useful to specifically dissect the function of viral and host factors in cell entry, which has been exploited for numerous viruses. Here we successfully created hRSVpp and show that they faithfully recapitulate key characteristics of parental hRSV cell entry. Importantly, hRSVpp accurately mirror hRSV resistance to small molecule fusion inhibitors and clinically approved therapeutic antibodies. Moreover, we observed highly different susceptibility of cell lines to hRSVpp infection and also between cell entry of hRSVpp types (with F protein alone or with SH, G and F proteins). This indicates differential expression of host factors determining hRSV cell entry between these cell lines and highlights that the hRSVpp system is useful to explore the functional properties of hRSV en
velope protein combinations. Therefore, this system will be highly useful to study hRSV cell entry and host factor usage and to explore antiviral strategies targeting hRSV cell entry.