Safety and immunogenicity of the PFP vaccine against respiratory syncytial virus (RSV): the Western blot assay aids in distinguishing immune responses of the PFP vaccine from RSV infection

AbstractRespiratory syncytial virus (RSV) infection is the leading cause of severe lower respiratory tract infections (LRTI) in infants worldwide. The immune responses to RSV infection are implicated in RSV pathogenesis but RSV immunopathogenesis in humans remains poorly understood. We previously demonstrated that IFN-λ1 is the principle interferon induced following RSV infection of infants and well-differentiated primary pediatric bronchial epithelial cells (WD-PBECs). Interestingly, RSV F interacts with the TLR4/CD14/MD2 complex to initiate secretion of pro-inflammatory cytokines, while TLR4 stimulation with house dust mite induces IFN-λ1 production. However, the role of TLR4 in RSV infection and concomitant IFN-λ1 induction remains unclear. Using our RSV/WD-PBEC infection model, we found that CLI-095 inhibition of TLR4 resulted in significantly reduced viral growth kinetics, and secretion of IFN-λ1 and pro-inflammatory chemokines. To elucidate specific TLR4 signalling intermediates implicated in virus replication and innate immune responses we selected 4 inhibitors, including LY294002, U0126, SB203580 and JSH-23. SB203580, a p38 MAPK inhibitor, reduced both viral growth kinetics and IFN-λ1 secretion, while JSH-23, an NF-κB inhibitor, reduced IFN-λ1 secretion without affecting virus growth kinetics. Our data indicate that TLR4 plays a role in RSV entry and/or replication and IFN-λ1 induction following RSV infection is mediated, in part, by TLR4 signalling through NF- κB and/or p38 MAPK. Therefore, targeting TLR4 or downstream effector proteins could present novel treatment strategies against RSV.ImportanceThe role of TLR4 in RSV infection and IFN-λ1 induction is controversial. Using our WD-PBEC model, which replicates many hallmarks of RSV infection in vivo, we demonstrated that the TLR4 pathway is involved in both RSV infection and/or replication and the concomitant induction of IFN-λ1 and other pro-inflammatory cytokines. Increasing our understanding of the role of TLR4 in RSV immunopathogenesis may lead to the development of novel RSV therapeutics.

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Streptococcus pneumoniae serotype 22F infection in respiratory syncytial virus infected neonatal lambs enhances morbidity

PLoS ONE ◽

10.1371/journal.pone.0235026 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0235026

Author(s):

Sarhad Alnajjar ◽

Panchan Sitthicharoenchai ◽

Jack Gallup ◽

Mark Ackermann ◽

David Verhoeven

Keyword(s):

Respiratory Syncytial Virus ◽

Streptococcus Pneumoniae ◽

Immune Responses ◽

Clinical Symptoms ◽

Dual Infection ◽

Lesion Development ◽

Viral Loads ◽

Rsv Infection ◽

Syncytial Virus ◽

Neonatal Lambs

Respiratory syncytial virus (RSV) is the primary cause of viral bronchiolitis resulting in hospitalization and a frequent cause of secondary respiratory bacterial infection, especially by Streptococcus pneumoniae (Spn) in infants. While murine studies have demonstrated enhanced morbidity during a viral/bacterial co-infection, human meta-studies have conflicting results. Moreover, little knowledge about the pathogenesis of emerging Spn serotype 22F, especially the co-pathologies between RSV and Spn, is known. Here, colostrum-deprived neonate lambs were divided into four groups. Two of the groups were nebulized with RSV M37, and the other two groups were mock nebulized. At day three post-RSV infection, one RSV group (RSV/Spn) and one mock-nebulized group (Spn only) were inoculated with Spn intratracheally. At day six post-RSV infection, bacterial/viral loads were assessed along with histopathology and correlated with clinical symptoms. Lambs dually infected with RSV/Spn trended with higher RSV titers, but lower Spn. Additionally, lung lesions were observed to be more frequent in the RSV/Spn group characterized by increased interalveolar wall thickness accompanied by neutrophil and lymphocyte infiltration and higher myeloperoxidase. Despite lower Spn in lungs, co-infected lambs had more significant morbidity and histopathology, which correlated with a different cytokine response. Thus, enhanced disease severity during dual infection may be due to lesion development and altered immune responses rather than bacterial counts.

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Contribution of Dendritic Cells in Protective Immunity against Respiratory Syncytial Virus Infection

Viruses ◽

10.3390/v12010102 ◽

2020 ◽

Vol 12 (1) ◽

pp. 102 ◽

Cited By ~ 2

Author(s):

Hi Eun Jung ◽

Tae Hoon Kim ◽

Heung Kyu Lee

Keyword(s):

Dendritic Cells ◽

Respiratory Syncytial Virus ◽

Immune Responses ◽

Defense Mechanisms ◽

Adaptive Immune Response ◽

The Elderly ◽

Effective Vaccine ◽

Adaptive Immune ◽

Rsv Infection ◽

Syncytial Virus

Respiratory syncytial virus (RSV) is a major cause of severe respiratory disease in infants and the elderly. The socioeconomic burden of RSV infection is substantial because it leads to serious respiratory problems, subsequent hospitalization, and mortality. Despite its clinical significance, a safe and effective vaccine is not yet available to prevent RSV infection. Upon RSV infection, lung dendritic cells (DCs) detecting pathogens migrate to the lymph nodes and activate the adaptive immune response. Therefore, RSV has evolved various immunomodulatory strategies to inhibit DC function. Due to the capacity of RSV to modulate defense mechanisms in hosts, RSV infection results in inappropriate activation of immune responses resulting in immunopathology and frequent reinfection throughout life. This review discusses how DCs recognize invading RSV and induce adaptive immune responses, as well as the regulatory mechanisms mediated by RSV to disrupt DC functions and ultimately avoid host defenses.

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

Journal of Virology ◽

10.1128/jvi.00302-10 ◽

2010 ◽

Vol 84 (18) ◽

pp. 9584-9594 ◽

Cited By ~ 12

Author(s):

Annemieke Schuurhof ◽

Louis Bont ◽

Jeroen L. A. Pennings ◽

Hennie M. Hodemaekers ◽

Piet W. Wester ◽

...

Keyword(s):

Gene Expression ◽

Immune Response ◽

Respiratory Syncytial Virus ◽

Immune Responses ◽

Innate Immune Response ◽

Innate Immune ◽

Transcription Profiles ◽

Rsv Infection ◽

Syncytial Virus ◽

Induced Immunity

ABSTRACT 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 (ΔG-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 ΔG-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.

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Plasmacytoid dendritic cells inhibit pulmonary immunopathology and promote clearance of respiratory syncytial virus

Journal of Experimental Medicine ◽

10.1084/jem.20052359 ◽

2006 ◽

Vol 203 (5) ◽

pp. 1153-1159 ◽

Cited By ~ 183

Author(s):

Joost J. Smit ◽

Brian D. Rudd ◽

Nicholas W. Lukacs

Keyword(s):

Dendritic Cells ◽

Respiratory Syncytial Virus ◽

Dendritic Cell ◽

Immune Responses ◽

Plasmacytoid Dendritic Cell ◽

Protective Role ◽

Plasmacytoid Dendritic Cells ◽

Rsv Infection ◽

Syncytial Virus ◽

Acquired Immune Responses

Respiratory syncytial virus (RSV) infection is widely spread and is a major cause of bronchiolitis in infants and high-risk adults, often leading to hospitalization. RSV infection leads to obstruction and inflammation of the airways and induction of innate and acquired immune responses. Because dendritic cells (DCs) are essential in the elicitation of these immune responses, we investigated the presence and the role of dendritic cell subtypes upon RSV infection in the lung. Here, we report that RSV infection increased the number of both conventional and plasmacytoid dendritic cells in the lung and the lung-draining lymph nodes. In particular, the increase in plasmacytoid dendritic cell numbers was sustained and lasted until 30 d after infection. Depletion of plasmacytoid dendritic cells resulted in decreased RSV clearance. In addition, depletion of plasmacytoid dendritic cells resulted in an exacerbation of all manifestations of immune-mediated pathology caused by RSV infection. In conclusion, this study demonstrates that both conventional and plasmacytoid dendritic cells are attracted to the site of RSV infection. It is demonstrated that plasmacytoid dendritic cells play a protective role during RSV infection by modulation of local immune responses.

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Local immune response to respiratory syncytial virus infection is diminished in senescence-accelerated mice

Journal of General Virology ◽

10.1099/vir.0.83089-0 ◽

2007 ◽

Vol 88 (9) ◽

pp. 2552-2558 ◽

Cited By ~ 25

Author(s):

Beixing Liu ◽

Yoshinobu Kimura

Keyword(s):

Respiratory Syncytial Virus ◽

T Lymphocytes ◽

Immune Responses ◽

Aged Mouse ◽

Virus Growth ◽

Cellular Immune Responses ◽

Age Related ◽

Rsv Infection ◽

Syncytial Virus ◽

Cellular Immune

The effect of ageing on the local defence system against respiratory syncytial virus (RSV) infection was investigated using an aged mouse model of the senescence-accelerated mouse (SAM) strain P1. Following intranasal infection with RSV, SAM-P1 mice showed a marked loss in weight, with elevated virus growth in the lungs and prolonged virus shedding. The increased susceptibility to RSV infection was associated mainly with diminished cellular immunity by local virus-specific cytotoxic T lymphocytes and natural killer cells. The deficiency in cellular immune responses was due to a lack of clonal expansion of CD4+ and CD8+ T lymphocytes, together with an imbalance of T-helper type 1 (Th1)/Th2 cytokine production in the respiratory tract, including the lungs. Furthermore, the production of virus-specific local IgA antibody was restrained. Prolonged virus loading in the lungs of SAM-P1 mice caused a massive infiltration of CD16+/32+ inflammatory cells, which was one factor responsible for severe pneumonia. The adoptive transfer of immune-competent spleen cells achieved an appreciable protection for SAM-P1 mice against RSV challenge infection. These results suggested that age-related immune dysfunction, especially defects in cellular immune responses, accounts for the increased morbidity and mortality in RSV infection of the elderly.

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Respiratory Syncytial Virus (RSV) Pulmonary Infection in Humanized Mice Induces Human Anti-RSV Immune Responses and Pathology

Journal of Virology ◽

10.1128/jvi.00259-16 ◽

2016 ◽

Vol 90 (10) ◽

pp. 5068-5074 ◽

Cited By ~ 14

Author(s):

Anurag Sharma ◽

Wenzhu Wu ◽

Biin Sung ◽

Jing Huang ◽

Tiffany Tsao ◽

...

Keyword(s):

Respiratory Syncytial Virus ◽

Immune Responses ◽

The Elderly ◽

Lavage Fluid ◽

Humanized Mice ◽

Human Immune System ◽

Nsg Mice ◽

Rsv Infection ◽

Human Immune ◽

Syncytial Virus

ABSTRACTRespiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease, which causes high rates of morbidity and mortality in infants and the elderly. Models of human RSV pulmonary disease are needed to better understand RSV pathogenesis and to assess the efficacy of RSV vaccines. We assessed the RSV-specific human innate, humoral, and cellular immune responses in humanized mice (mice with a human immune system [HIS mice]) with functional human CD4+T and B cells. These mice were generated by introduction of HLA class II genes, various human cytokines, and human B cell activation factor into immunodeficient NOD scid gamma (NSG) mice by the use of an adeno-associated virus vector, followed by engraftment of human hematopoietic stem cells. During the first 3 days of infection, HIS mice lost more weight and cleared RSV faster than NSG mice. Human chemokine (C-C motif) ligand 3 (CCL3) and human interleukin-1β (IL-1β) expression was detected in the RSV-infected HIS mice. The pathological features induced by RSV infection in HIS mice included peribronchiolar inflammation, neutrophil predominance in the bronchioalveolar lavage fluid, and enhanced airway mucus production. Human anti-RSV IgG and RSV-neutralizing antibodies were detected in serum and human anti-RSV mucosal IgA was detected in bronchioalveolar lavage fluid for up to 6 weeks. RSV infection induced an RSV-specific human gamma interferon response in HIS mouse splenocytes. These results indicate that human immune cells can induce features of RSV lung disease, including mucus hyperplasia, in murine lungs and that HIS mice can be used to elicit human anti-RSV humoral and cellular immunity.IMPORTANCEInfections with respiratory syncytial virus (RSV) are common and can cause severe lung disease in infants and the elderly. The lack of a suitable animal model with disease features similar to those in humans has hampered efforts to predict the efficacy of novel anti-RSV therapies and vaccines for use in humans. A murine model consisting of mice with a human immune system (HIS mice) could be useful for assessment of RSV disease and anti-RSV responses specific to humans. This study investigates an HIS mouse model to imitate human RSV disease and immune responses. We found that RSV lung infection in HIS mice results in an RSV-specific pathology that mimics RSV disease in humans and induces human anti-RSV immune responses. This model could be useful for better understanding of human RSV disease and for the development of RSV therapies.

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Priming with a Secreted Form of the Fusion Protein of Respiratory Syncytial Virus (RSV) Promotes Interleukin-4 (IL-4) and IL-5 Production but Not Pulmonary Eosinophilia following RSV Challenge

Journal of Virology ◽

10.1128/jvi.73.12.10086-10094.1999 ◽

1999 ◽

Vol 73 (12) ◽

pp. 10086-10094 ◽

Cited By ~ 32

Author(s):

Gary P. Bembridge ◽

Juan A. Lopez ◽

Regla Bustos ◽

Jose A. Melero ◽

Roy Cook ◽

...

Keyword(s):

Respiratory Syncytial Virus ◽

Immune Responses ◽

G Protein ◽

Interleukin 4 ◽

Soluble Form ◽

Interferon Production ◽

F Protein ◽

The Face ◽

Rsv Infection ◽

Syncytial Virus

ABSTRACT The attachment (G) protein of respiratory syncytial virus (RSV) is synthesized as two mature forms: a membrane-anchored form and a smaller secreted form. BALB/c mice scarified with vaccinia virus (VV) expressing the secreted form develop a greater pulmonary eosinophilic influx following RSV challenge than do mice scarified with VV expressing the membrane-anchored form. To determine if a soluble form of an RSV protein was sufficient to induce eosinophilia following RSV challenge, a cDNA that encoded a secreted form of the fusion (F) protein of RSV was constructed and expressed in VV (VV-Ftm−). Splenocytes and lung lymphocytes from mice primed with VV-Ftm− produced significantly more of the Th2 cytokines interleukin-4 (IL-4) and IL-5 than did mice vaccinated with VV expressing either the native (membrane-anchored) form of the F protein or the G protein. Although mice scarified with VV-Ftm− developed a slight increase in the number of pulmonary eosinophils following RSV infection, the increase was not as great as that seen in VV-G-primed mice. Despite the increased IL-4 and IL-5 production and in contrast to mice primed with VV-G, mice primed with VV-Ftm− developed RSV-specific cytotoxic T lymphocytes (CTL) and maintained high levels of gamma interferon production. These data demonstrate that recombinant VV strains expressing soluble forms of RSV proteins induce immune responses that are more Th2-like. However, this change alone does not appear sufficient to induce vaccine-augmented disease in the face of active CD8+ CTL populations.

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