Chimeric calicivirus-like particles elicit specific immune responses in pigs

Area of Science:

• Veterinary Immunology
• Vaccinology
• Molecular Virology

Background:

• Virus-like particles (VLPs) are promising platforms for vaccine development.
• Rabbit haemorrhagic disease virus (RHDV) VLPs have demonstrated efficacy in inducing immune responses in mice.
• Assessing novel vaccine vectors in pigs is crucial for veterinary applications.

Purpose of the Study:

• To evaluate the immunogenicity of chimeric RHDV-VLPs as vaccine vectors in pigs.
• To investigate the immune response elicited by RHDV-VLPs carrying a foot-and-mouth disease virus (FMDV) T epitope.
• To compare different administration routes (intranasal vs. intramuscular) and adjuvant effects.

Main Methods:

• Generation of chimeric RHDV-VLPs incorporating a 3A protein T epitope from FMDV.
• In vitro activation of porcine bone marrow-derived dendritic cells (poBMDCs) by RHDV-VLPs.
• Intranasal and intramuscular inoculation of pigs with chimeric RHDV-VLPs, with and without adjuvant (Montanide™ ISA 206).
• Measurement of specific IgG and IgA antibody responses, IFN-γ-secreting cells (ELISPOT), and T cell proliferation.

Main Results:

• Chimeric RHDV-VLPs activated immature porcine dendritic cells.
• Both IgG and IgA antibodies against RHDV-VLPs were induced in pigs.
• Intramuscular administration resulted in higher anti-RHDV-VLP IgA responses compared to intranasal delivery.
• The group receiving intramuscular RHDV-VLPs with adjuvant showed significantly higher antibody titers and T cell responses (IFN-γ and proliferation) against the 3A epitope and RHDV-VLPs.

Conclusions:

• Chimeric RHDV-VLPs are immunogenic in pigs and can serve as effective antigen carriers.
• Adjuvant use enhances the immune response elicited by chimeric RHDV-VLPs.
• This study presents the first report on the potential of chimeric RHDV-VLPs as antigen carriers in swine immunology.