A prime-boost vaccination strategy using attenuated Salmonella typhimurium and a replication-deficient recombinant adenovirus vector elicits protective immunity against human respiratory syncytial virus

Area of Science:

• Immunology
• Vaccinology
• Virology

Background:

• Human respiratory syncytial virus (RSV) is a major pediatric pathogen, yet no approved vaccine exists.
• Existing vaccine development strategies for RSV have faced challenges.
• There is an urgent need for effective vaccine-enhancing strategies against RSV.

Purpose of the Study:

• To evaluate a heterologous prime-boost immunization regimen for RSV vaccine development.
• To investigate the immune response generated by an oral SL7207/pcDNA3.1/F prime followed by an intranasal FGAd/F boost.
• To assess the efficacy of this prime-boost strategy against RSV challenge.

Main Methods:

• Mice were immunized with an oral SL7207/pcDNA3.1/F prime followed by an intranasal FGAd/F boost.
• RSV-specific humoral, mucosal, and cellular immune responses were measured.
• Histopathological analysis was performed after RSV challenge.

Main Results:

• The heterologous prime-boost regimen induced stronger RSV-specific humoral and mucosal immune responses compared to oral vaccination alone.
• This strategy elicited stronger specific cellular immune responses than intranasal vaccination alone.
• Histopathological findings indicated enhanced efficacy against RSV challenge with the prime-boost approach.

Conclusions:

• A heterologous prime-boost strategy using oral SL7207/pcDNA3.1/F and intranasal FGAd/F enhances immune responses against RSV.
• This approach improves vaccine efficacy compared to single-vector regimens.
• The findings suggest potential for this prime-boost strategy in future RSV vaccine development.