Project description:Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract viral disease in infants and young children. Presently, there are no explicit recommendations for RSV treatment apart from supportive care. The virus is therefore responsible for an estimated 160,000 deaths per year worldwide. Despite half a century of dedicated research, there remains no licensed vaccine product. Herein are described past and current efforts to harness innate and adaptive immune potentials to combat RSV. A plethora of candidate vaccine products and strategies are reviewed. The development of a successful RSV vaccine may ultimately stem from attention to historical lessons, in concert with an integral partnering of immunology and virology research fields.
Project description:In accompanying papers (P. L. Acosta, M. T. Caballero, and F. P. Polack, Clin Vaccine Immunol 23:189-195, 2016, http://dx.doi.org/10.1128/CVI.00609-15; M. Vissers, I. M. L. Ahout, M. I. de Jonge, and G. Ferwerda, Clin Vaccine Immunol 23:243-245, 2016, http://dx.doi.org/10.1128/CVI.00590-15) in this issue of Clinical and Vaccine Immunology, the history of and immune mechanisms underlying vaccine-enhanced respiratory syncytial virus (RSV) disease and of investigations of mucosal antibodies and their association with viral load in RSV-infected children, respectively, are described. This commentary discusses RSV vaccine candidates, target populations, and the challenges associated with achieving a safe and effective vaccine.
Project description:Respiratory syncytial virus (RSV) is a major cause of pneumonia and wheezing in infants and the elderly, but to date there is no licensed vaccine. We developed a gold nanorod construct that displayed the major protective antigen of the virus, the fusion protein (F). Nanorods conjugated to RSV F were formulated as a candidate vaccine preparation by covalent attachment of viral protein using a layer-by-layer approach. In vitro studies using ELISA, electron microscopy and circular dichroism revealed that conformation-dependent epitopes were maintained during conjugation, and transmission electron microscopy studies showed that a dispersed population of particles could be achieved. Human dendritic cells treated with the vaccine induced immune responses in primary human T cells. These results suggest that this vaccine approach may be a potent method for immunizing against viruses such as RSV with surface glycoproteins that are targets for the human immune response.
Project description:Respiratory syncytial virus (RSV) is a major cause of infectious lower respiratory disease in infants and the elderly. As there is no vaccine for RSV, we developed a genetic vaccine approach that induced protection of the entire respiratory tract from a single parenteral administration. The approach was based on adenovirus vectors derived from newly isolated nonhuman primate viruses with low seroprevalence. We show for the first time that a single intramuscular (IM) injection of the replication-deficient adenovirus vectors expressing the RSV fusion (F0) glycoprotein induced immune responses that protected both the lungs and noses of cotton rats and mice even at low doses and for several months postimmunization. The immune response included high titers of neutralizing antibody that were maintained ? 24 weeks and RSV-specific CD8+ and CD4+ T cells. The vectors were as potently immunogenic as a human adenovirus 5 vector in these two key respiratory pathogen animal models. Importantly, there was minimal alveolitis and granulocytic infiltrates in the lung, and type 2 cytokines were not produced after RSV challenge even under conditions of partial protection. Overall, this genetic vaccine is highly effective without potentiating immunopathology, and the results support development of the vaccine candidate for human testing.
Project description:The human respiratory syncytial virus (hRSV) is the causative agent for high rates of hospitalizations due to viral bronchiolitis and pneumonia worldwide. Such a disease is characterized by an infection of epithelial cells of the distal airways that leads to inflammation and subsequently to respiratory failure. Upon infection, different pattern recognition receptors recognize the virus and trigger the innate immune response against the hRSV. Further, T cell immunity plays an important role for virus clearance. Based on animal studies, it is thought that the host immune response to hRSV is based on a biased T helper (Th)-2 and Th17 T cell responses with the recruitment of T cells, neutrophils and eosinophils to the lung, causing inflammation and tissue damage. In contrast, human immunity against RSV has been shown to be more complex with no definitive T cell polarization profile. Nowadays, only a humanized monoclonal antibody, known as palivizumab, is available to protect against hRSV infection in high-risk infants. However, such treatment involves several injections at a significantly high cost. For these reasons, intense research has been focused on finding novel vaccines or therapies to prevent hRSV infection in the population. Here, we comprehensively review the recent literature relative to the immunological features during hRSV infection, as well as the new insights into preventing the disease caused by this virus.
Project description:Bovine respiratory syncytial virus (BRSV) and human respiratory syncytial virus (HRSV) are major causes of respiratory disease in calves and children, respectively, and are priorities for vaccine development. We previously demonstrated that an experimental vaccine, BRSV-immunostimulating complex (ISCOM), is effective in calves with maternal antibodies. The present study focuses on the antigenic characterization of this vaccine for the design of new-generation subunit vaccines. The results of our study confirmed the presence of membrane glycoprotein (G), fusion glycoprotein (F), and nucleoprotein (N) proteins in the ISCOMs, and this knowledge was extended by the identification of matrix (M), M2-1, phosphoprotein (P), small hydrophobic protein (SH) and of cellular membrane proteins, such as the integrins ?V?1, ?V?3, and ?3?1. The quantity of the major protein F was 4- to 5-fold greater than that of N (?77 ?g versus ?17 ?g/calf dose), whereas G, M, M2-1, P, and SH were likely present in smaller amounts. The polymerase (L), M2-2, nonstructural 1 (NS1), and NS2 proteins were not detected, suggesting that they are not essential for protection. Sera from the BRSV-ISCOM-immunized calves contained high titers of IgG antibody specific for F, G, N, and SH. Antibody responses against M and P were not detected; however, this does not exclude their role in protective T-cell responses. The absence of immunopathological effects of the cellular proteins, such as integrins, needs to be further confirmed, and their possible contribution to adjuvant functions requires elucidation. This work suggests that a combination of several surface and internal proteins should be included in subunit RSV vaccines and identifies absent proteins as potential candidates for differentiating infected from vaccinated animals.