Respiratory Syncytial Virus Grown in Vero Cells Contains a Truncated Attachment Protein That Alters Its Infectivity and Dependence on Glycosaminoglycans

Division of Immunology, The Graduate College, Rush University, 1653 W. Congress Parkway, Chicago, Illinois 60612, USA.
Journal of Virology (Impact Factor: 4.44). 09/2009; 83(20):10710-8. DOI: 10.1128/JVI.00986-09
Source: PubMed


Human respiratory syncytial virus (RSV) contains a heavily glycosylated 90-kDa attachment glycoprotein (G). Infection of HEp-2 and Vero cells in culture depends largely on virion G protein binding to cell surface glycosaminoglycans (GAGs). This GAG-dependent phenotype has been described for RSV grown in HEp-2 cells, but we have found that it is greatly reduced by a single passage in Vero cells. Virions produced from Vero cells primarily display a 55-kDa G glycoprotein. This smaller G protein represents a post-Golgi compartment form that is lacking its C terminus, indicating that the C terminus is required for GAG dependency. Vero cell-grown virus infected primary well-differentiated human airway epithelial (HAE) cell cultures 600-fold less efficiently than did HEp-2 cell-grown virus, indicating that the C terminus of the G protein is also required for virus attachment to this model of the in vivo target cells. This reduced infectivity for HAE cell cultures is not likely to be due to the loss of GAG attachment since heparan sulfate, the primary GAG used by RSV for attachment to HEp-2 cells, is not detectable at the apical surface of HAE cell cultures where RSV enters. Growing RSV stocks in Vero cells could dramatically reduce the initial infection of the respiratory tract in animal models or in volunteers receiving attenuated virus vaccines, thereby reducing the efficiency of infection or the efficacy of the vaccine.

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Available from: Mark Peeples, Oct 02, 2015
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    • "Additionally, lower levels of viral RNA were detected in intranasal Vero (INV) than in either method of inoculation with HEp-2-grown virus. Although this is a limited study, the in vivo results, demonstrating differences in viral infectivity, are consistent with the in vitro mechanistic studies demonstrating differences in the G glycoprotein expression by RSV grown in Vero cells, that were confirmed in data shown in the present study, and which can result in decreased attachment of the virus to epithelial cells [13,14,15,16,17,18,19,20,21,22,23,24,27,28,29]. "
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    ABSTRACT: Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants and young children. A small percentage of these individuals develop severe and even fatal disease. To better understand the pathogenesis of severe disease and develop therapies unique to the less-developed infant immune system, a model of infant disease is needed. The neonatal lamb pulmonary development and physiology is similar to that of infants, and sheep are susceptible to ovine, bovine, or human strains of RSV. RSV grown in Vero (African green monkey) cells has a truncated attachment G glycoprotein as compared to that grown in HEp-2 cells. We hypothesized that the virus grown in HEp-2 cells would cause more severe clinical symptoms and cause more severe pathology. To confirm the hypothesis, lambs were inoculated simultaneously by two different delivery methods (intranasal and nebulized inoculation) with either Vero-grown or HEp-2-grown RSV Memphis 37 (M37) strain of virus to compare viral infection and disease symptoms. Lambs infected with HEp-2 cell-derived virus by either intranasal or nebulization inoculation had significantly higher levels of viral RNA in lungs as well as greater clinical disease including both gross and histopathologic lesions compared to lambs similarly inoculated with Vero-grown virus. Thus, our results provide convincing in vivo evidence for differences in viral infectivity that corroborate previous in vitro mechanistic studies demonstrating differences in the G glycoprotein expression by RSV grown in Vero cells.
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    • "The F protein appears to be a more efficient neutralizing and protective antigen compared to G [5]. This may be related among others to the high carbohydrate content of the G protein, which may shield the protein from immune recognition [6], [7]. In addition, the G protein is also secreted from infected cells [8], [9], in which form it may function as an antigen decoy [10]. "
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