Immune Responses to Adjuvanted H7N9 Split Antigen in Aged Mice

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Avian influenza A H7N9 poses a severe risk to humans, particularly the elderly, due to age-related immune decline and potentially low vaccine efficacy.
• The immunogenicity of H7 hemagglutinin in older adults is a concern for vaccine effectiveness.

Purpose of the Study:

• To assess the efficacy of an adjuvant, MF59, in enhancing immune responses to a split avian influenza A H7N9 vaccine in aged mice.
• To compare humoral and cellular immune responses in elderly mice receiving the vaccine with and without MF59.

Main Methods:

• A recombinant H7N9 influenza virus was generated using reverse genetics.
• Split avian influenza A H7N9 vaccine with and without MF59 adjuvant was administered to 18-month-old BALB/c mice.
• Humoral (hemagglutination inhibition, microneutralization) and cellular (interferon-gamma ELISPOT) immune responses were measured.

Main Results:

• Aged mice immunized with the H7N9 vaccine plus MF59 showed significantly higher hemagglutination inhibition and microneutralization antibody titers compared to those receiving the vaccine alone.
• MF59 adjuvant also boosted interferon-gamma-specific enzyme-linked immunospot assay (ELISPOT) responses in aged mice.
• The study demonstrated dose-dependent immune responses with the adjuvant.

Conclusions:

• The split avian influenza A H7N9 vaccine combined with the MF59 adjuvant significantly enhances both humoral and cellular immune responses in aged mice.
• MF59 adjuvant holds potential for improving the immunogenicity and efficacy of influenza vaccines in elderly populations.
• This strategy may offer a better protective approach against avian influenza A H7N9 for vulnerable older adults.