A highly attenuated recombinant human respiratory syncytial virus lacking the G protein induces long-lasting protection in cotton rats

Respiratory syncytial virus (RSV) causes severe respiratory disease in young children. Antibodies specific for the RSV prefusion F protein have guided RSV vaccine research, and in human serum, these antibodies contribute to Ͼ90% of the neutralization response; however, detailed insight into the composition of the human B cell repertoire against RSV is still largely unknown. In order to study the B cell repertoire of three healthy donors for specificity against RSV, CD27 ϩ memory B cells were isolated and immortalized using BCL6 and Bcl-xL. Of the circulating memory B cells, 0.35% recognized RSV-A2-infected cells, of which 59% were IgAexpressing cells and 41% were IgG-expressing cells. When we generated monoclonal B cells selected for high binding to RSV-infected cells, 44.5% of IgGexpressing B cells and 56% of IgA-expressing B cells reacted to the F protein, while, unexpectedly, 41.5% of IgG-expressing B cells and 44% of IgA expressing B cells reacted to the G protein. Analysis of the G-specific antibodies revealed that 4 different domains on the G protein were recognized. These epitopes predicted cross-reactivity between RSV strain A (RSV-A) and RSV-B and matched the potency of antibodies to neutralize RSV in HEp-2 cells and in primary epithelial cell cultures. G-specific antibodies were also able to induce antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis of RSV-A2-infected cells. However, these processes did not seem to depend on a specific epitope. In conclusion, healthy adults harbor a diverse repertoire of RSV glycoprotein-specific antibodies with a broad range of effector functions that likely play an important role in antiviral immunity.IMPORTANCE Human RSV remains the most common cause of severe lower respiratory tract disease in premature babies, young infants, the elderly, and immunocompromised patients and plays an important role in asthma exacerbations. In developing countries, RSV lower respiratory tract disease has a high mortality. Without an effective vaccine, only passive immunization with palivizumab is approved for prophylactic treatment. However, highly potent RSV-specific monoclonal antibodies could potentially serve as a therapeutic treatment and contribute to disease control and mortality reduction. In addition, these antibodies could guide further vaccine development. In this study, we isolated and characterized several novel antibodies directed at the RSV G protein. This information can add to our understanding and treatment of RSV disease.

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Broadly Reactive Anti-Respiratory Syncytial Virus G Antibodies from Exposed Individuals Effectively Inhibit Infection of Primary Airway Epithelial Cells

Cortjens

Yasuda

et al. 2017

“…The propagation of virus and preparation of vaccine were described in detail previously (17). In brief, the HRSV that we used for infection and challenge experiments was wild-type HRSV-X (wtHRSV) (strain 98-25147-X).…”

Section: Methodsmentioning

confidence: 99%

“…HRSV is a good example, as infection, pathology, and protection induced by candidate HRSV vaccines in cotton rats have already been explored and reflect the human situation (11,12,(15)(16)(17). In comparison to young cotton rats, aged cotton rats express a prolonged cytokine response and a high degree of pathology in the lungs in response to a primary HRSV infection (18,19).…”

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confidence: 99%

Impaired Immune Response to Vaccination against Infection with Human Respiratory Syncytial Virus at Advanced Age

Guichelaar

Hoeboer

Widjojoatmodjo

et al. 2014

Self Cite

Elderly humans are prone to severe infection with human respiratory syncytial virus (HRSV). The aging of today's human population warrants the development of protective vaccination strategies aimed specifically at the elderly. This may require special approaches due to deteriorating immune function. To design and test vaccination strategies tailored to the elderly population, we need to understand the host response to HRSV vaccination and infection at old age. Moreover, the preclinical need for testing of candidate vaccines requires translational models resembling susceptibility to the (unadapted) human pathogen. Here, we explored the effects of aging on immunity and protection induced by a model HRSV vaccine candidate in a translational aging model in cotton rats (Sigmodon hispidus) and examined possibilities to optimize vaccination concepts for the elderly. We immunized young and aged cotton rats with a live-attenuated recombinant HRSV vaccine candidate and analyzed the induced immune response to and protection against challenge with HRSV. In old cotton rats, HRSV infection persisted longer, and vaccination induced less protection against infection. Aged animals developed lower levels of vaccine-induced IgG, virus-neutralizing serum antibodies, and IgA in lungs. Moreover, booster responses to HRSV challenge were impaired in animals vaccinated at an older age. However, increased dose and reduced attenuation of vaccine improved protection even in old animals. This study shows that cotton rats provide a model for studying the effects of aging on the immune response to the human respiratory pathogen HRSV and possibilities to optimize vaccine concepts for the elderly. IMPORTANCEHRSV infection poses a risk for severe disease in the elderly. The aging of the population warrants increased efforts to prevent disease at old age, whereas HRSV vaccines are only in the developmental phase. The preclinical need for testing of candidate human vaccines requires translational models resembling susceptibility to the natural human virus. Moreover, we need to gain insight into waning immunity at old age, as this is a special concern in vaccine development. In this study, we explored the effect of age on protection and immunity against an experimental HRSV vaccine in aged cotton rats (Sigmodon hispidus), a rodent species that provides a model representing natural susceptibility to human viruses. Older animals generate fewer antibodies upon vaccination and require a higher vaccine dose for protection. Notably, during the early secondary immune response to subsequent HRSV infection, older animals showed less protection and a slower increase of the virus-neutralizing antibody titer.

“…Recombinant RSV virus lacking the G gene (⌬G-RSV) was generated by reverse genetics. The construction and characterization of this mutant have been described previously (43). The recombinant virus was cultured on monkey kidney Vero cells (ECACC lot 10-87/CCL-81; ATCC).…”

Section: Methodsmentioning

confidence: 99%

Gene Expression Differences in Lungs of Mice during Secondary Immune Responses to Respiratory Syncytial Virus Infection

Schuurhof

Bont

Pennings³

et al. 2010

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Vaccine-induced immunity has been shown to alter the course of a respiratory syncytial virus (RSV) infection both in murine models and in humans. To elucidate which mechanisms underlie the effect of vaccine-induced immunity on the course of RSV infection, transcription profiles in the lungs of RSV-infected mice were examined by microarray analysis. Three models were used: RSV reinfection as a model for natural immunity, RSV challenge after formalin-inactivated RSV vaccination as a model for vaccine-enhanced disease, and RSV challenge following vaccination with recombinant RSV virus lacking the G gene (⌬G-RSV) as a model for vaccine-induced immunity. Gene transcription profiles, histopathology, and viral loads were analyzed at 1, 2, and 5 days after RSV challenge. On the first 2 days after challenge, all mice displayed an expression pattern in the lung similar of that found in primary infection, showing a strong innate immune response. On day 5 after RSV reinfection or after challenge following ⌬G-RSV vaccination, the innate immune response was waning. In contrast, in mice with vaccine-enhanced disease, the innate immune response 5 days after RSV challenge was still present even though viral replication was diminished. In addition, only in this group was Th2 gene expression induced. These findings support a hypothesis that vaccine-enhanced disease is mediated by prolonged innate immune responses and Th2 polarization in the absence of viral replication.Respiratory syncytial virus (RSV) infection in infants can cause morbidity ranging from mild upper respiratory tract symptoms to severe bronchiolitis and even mortality (29). A small proportion of infected infants need hospitalization, whereas the majority develop only upper respiratory tract infection and recover in an outpatient setting (14). Known risk factors for more severe disease in children are age younger than 3 months, preterm birth, chronic lung disease of prematurity, congenital heart disease, Down's syndrome, cystic fibrosis, and immunodeficiency disorders (1,30,37). Besides infants, specific adult populations also are at risk to develop severe RSV infection, such as adults who are immunocompromised, aged, or institutionalized or have underlying diseases (8, 13). Both immunological mechanisms and virus-induced cytopathology may be keys to the variable severity of RSV bronchiolitis in infancy. The association between naturally occurring polymorphisms in innate immune response genes and the susceptibility to severe RSV bronchiolitis supports this theory (15,16,20,32).Murine models are widely used to study RSV-induced pathology. However, differences in RSV pathogenesis in relation to the genetic background of the mouse strain used have been described (19). These murine models have shown that a complex immune response is induced by RSV infection. However, high viral titers are needed to induce consistent histopathological changes in the lung (12). Generally, mice clear the virus without suffering severe lung pathology. Vaccination of mice with formalin-inac...