Introduction
Respiratory syncytial virus (RSV) poses a significant threat, particularly to infants, young children, and older adults, causation acute respiratory infections. With over 30 million infants worldwide descending prey to RSV every year, it becomes material to find a vaccine that can battle this virus.Hospitalization is required for about 10% of the affected infants. Alarmingly, RSV infektions can be as severe as influenza in older adults, resulting in thousands of deaths and hospitalizations annually. In this article we will explore the RSV vaccine effectiveness across all ages considering immune senescence and recurrent infektions.
The Challenge of Reinfections
RSV is categorized into two antigenic groups, A and B, with multiple genotypes based on variations in the attachment glycoprotein (G) region. However, reinfections do not always occur due to different genotypes or subtypes. Surprisingly, the same genotype often leads to multiple reinfections. This highlights the complexity of developing vaccines that can generate high antibody titers while considering immune senescence in the elderly.
Study Overview: Evaluating an Innovative RSV Vaccine
In a recent study published in Viruses, Researchers evaluated VLP vaccine efficacy in young and elderly rats, considering age and previous RSV infections to understand vaccine effectiveness.
The VLP vaccine used in the study contained the fusion glycoprotein (F) and G protein of RSV, alongside the matrix (M) and nucleocapsid (NP) core proteins from the Newcastle disease virus (NDV). To validate the pre-fusion confirmation, the researchers employed Western blot assays using F protein-specific monoclonal antibodies. Antibodies against the G protein and the heptad repeat 2 (HR2) domain were utilized to quantify the RSV G and F proteins in the soluble VLP preparations.
To assess the vaccine’s efficacy, the researchers immunized young and elderly cotton rats with the VLP vaccine and subsequently exposed them to RSV. They employed plaque reduction assays to measure the neutralizing antibody titers against RSV. To evaluate various aspects of the immune response and protection, they conducted lung histopathology, real-time polymerase undefined response (RT-PCR), and enzyme-linked immunosorbent essay (ELISA).
Promising Results: Effective Immune Response in Young and Old Rats
The study’s findings were extremely promising. Both elderly and young cotton rats immunized with the VLP vaccine exhibited comparable levels of neutralizing antibody titers against RSV. Furthermore, both age groups demonstrated similar production of immunoglobulin G (IgG) levels against the RSV G and pre-fusion F proteins. The level of protection against RSV infection was also similar, indicating successful delivery of the G and F proteins by the VLP vaccine and the activation of comparable immune responses in both young and elderly populations.
A remarkable discovery was that a single dose of the VLP candidate vaccine in rats with previous RSV infections triggered immune memory established during previous encounters with RSV. This immune memory then generated protective immune responses in both young and elderly cotton rats to the same extent. Additionally, comparing neutralizing antibody titers between cotton rats vaccinated early in life and those vaccinated later revealed similar levels. This suggests that early vaccination against RSV can provide significant and lifelong protection.
Conclusion: Unveiling the Potential of RSVVaccination
Immunization with VLPs demonstrated the ability to induce comparable levels of neutralizing antibody titers against RSV in both young and elderly cotton rats with prior RSV infections. This vaccination approach also resulted in the production of IgG levels against the G and pre-F proteins, while effectively eliciting similar levels of protection upon RSV challenge.
In conclusion, the study highlights the immense potential of VLP-based immunization against RSV. Early RSV infections can establish immune memory in cotton rats, enabling efficient immunization with VLPs, paving the way for universal RSV vaccine development.