An Orthogonal Nanoadjuvant-Based RSV Subunit Vaccine Unlocks Potent Immunity through a High-Entropy-like...

Area of Science:

• Immunology
• Nanotechnology
• Vaccinology

Background:

• Respiratory syncytial virus (RSV) causes significant lower respiratory tract infections, particularly in vulnerable populations like infants and the elderly.
• Developing a potent and clinically viable RSV vaccine remains a challenge, especially regarding the induction of sufficient cellular immunity.
• Current RSV F subunit vaccines often struggle to elicit robust and long-lasting cellular immune responses.

Purpose of the Study:

• To develop an orthogonal nanoadjuvant-based nanovaccine platform to overcome the limitations of insufficient cellular immunity in RSV F subunit vaccination.
• To investigate the synergistic immune activation elicited by a novel Mn/Al-layered double hydroxide (Mn/Al-LDH) nanosheet functionalized with RSV F antigen and poly-CpG motifs.
• To evaluate the efficacy of this nanovaccine in enhancing both humoral and cellular immunity, and its protective effect against RSV challenge in murine models.

Main Methods:

• Construction of a nanovaccine using Mn/Al-LDH nanosheets functionalized with RSV F antigen and poly-CpG motifs.
• Assessment of adjuvant effects: Al for humoral immunity, Mn and CpG for cellular immunity via cGAS-STING and TLR pathways.
• Evaluation of immune response in murine models, including viral load reduction, lung pathology mitigation, and analysis of T cell subsets (CD4+, CD8+, TCM, CD134+).

Main Results:

• The nanovaccine demonstrated a synergistic "high-entropy" immunostimulatory effect, activating multiple immune pathways.
• Significant recruitment and activation of potent CD4+ and CD8+ T cells were observed, leading to rapid antigen-specific immune activation.
• The nanovaccine induced robust long-term T cell memory, evidenced by an expanded CD134+ subset within central memory T cells (TCM).
• In murine challenge models, the nanovaccine significantly reduced viral load and lung pathology compared to traditional aluminum (Al)-based vaccines.

Conclusions:

• The developed nanovaccine platform effectively addresses the challenge of insufficient cellular immunity in RSV vaccination.
• The orthogonal nanoadjuvant strategy orchestrates potent humoral and cellular immune responses, establishing durable immunological memory.
• This approach represents a new paradigm for efficacious RSV vaccine development and is potentially applicable to other challenging pathogens.