Sequential Immunization with Vaccines Based on SARS-CoV-2 Virus-like Particles Induces Broadly Neutralizing...

Area of Science:

• Virology
• Immunology
• Vaccine Development

Background:

• Despite widespread COVID-19 vaccination, SARS-CoV-2 infections persist, highlighting the need for improved vaccines against evolving variants.
• Emerging infectious diseases, termed "Disease X", necessitate adaptable immunization strategies.

Purpose of the Study:

• To evaluate the efficacy of sequential immunization strategies using virus-like particles (VLPs) based on SARS-CoV-2 variants.
• To determine if variant-based VLPs offer superior immunity against future SARS-CoV-2 variants.

Main Methods:

• Constructed VLPs for Wuhan-Hu-1 (prototype), Delta (δ), and Omicron (ο) SARS-CoV-2 variants using a baculovirus-insect expression system.
• Assessed immune responses in a mouse model using homologous prime-boost, heterologous prime-boost, and sequential immunization strategies.

Main Results:

• Sequential immunization (pro+δ+ο) demonstrated enhanced neutralizing antibody responses compared to other strategies.
• Sequential strategies also promoted CD4+ and CD8+ T lymphocyte proliferation and a Th1 cytokine profile.

Conclusions:

• Sequential immunization with SARS-CoV-2 variant-derived spike protein VLPs is a potential vaccine strategy.
• This approach may offer broad protection against emerging variants and future infectious diseases ('Disease X').