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Polymers (Basel)
. 2026 Mar 5;18(5):642.
doi: 10.3390/polym18050642.
Effects of Antigen Dosage and Chitosan Micro/Nanoparticle Size on Immune Responses in Mice Immunized with H5N1 Influenza Vaccine
Anh Dzung Nguyen 1 , Yen Nhi Nguyen 2 , Hong Pham 3 , Tam Duong Le Ha 2 , Hanh Lan Nguyen 2 , Lien Le 2 , Van Bon Nguyen 1 , Dinh Sy Nguyen 1 , Huu **** Dinh 4 , San-Lang Wang 5 , Van Cao 2
Affiliations
Highly pathogenic avian influenza A/H5N1 remains a persistent threat to public health and poultry production. H5N1 antigens are typically poorly immunogenic and require effective adjuvants for antigen dose-sparing. Here, we evaluated chitosan microparticles (CSMs) and nanoparticles (CSNs) as polymeric nano-adjuvants for an H5N1 influenza vaccine, focusing on the roles of antigen dose and particle size. A purified hemagglutinin antigen was adsorbed onto chitosan particles at doses ranging from 0.15 to 5.0 µg. Both CSNs and CSMs showed consistently high loading efficiency (97-99%). BALB/c mice were immunized intramuscularly in a prime-boost schedule. Chitosan nanoparticles significantly enhanced IgG and hemagglutination inhibition (HI) titers at low antigen doses compared with aluminum hydroxide and antigen-only controls (p < 0.05). Immune responses reached saturation at a 1.5 µg dose of antigen for chitosan nanoparticles and 3.0 µg for chitosan microparticles. IgG subtype analysis suggested a balanced IgG1/IgG2a profile. Collectively, these findings support chitosan-based polymeric nanoparticles as promising adjuvants enabling dose-sparing H5N1 vaccination.
Keywords: H5N1 influenza vaccine; antigen dose-sparing; chitosan; hemagglutination inhibition; microparticles; nanoparticles; polymeric adjuvant.
. 2026 Mar 5;18(5):642.
doi: 10.3390/polym18050642.
Effects of Antigen Dosage and Chitosan Micro/Nanoparticle Size on Immune Responses in Mice Immunized with H5N1 Influenza Vaccine
Anh Dzung Nguyen 1 , Yen Nhi Nguyen 2 , Hong Pham 3 , Tam Duong Le Ha 2 , Hanh Lan Nguyen 2 , Lien Le 2 , Van Bon Nguyen 1 , Dinh Sy Nguyen 1 , Huu **** Dinh 4 , San-Lang Wang 5 , Van Cao 2
Affiliations
- PMID: 41829340
- PMCID: PMC12986634
- DOI: 10.3390/polym18050642
Highly pathogenic avian influenza A/H5N1 remains a persistent threat to public health and poultry production. H5N1 antigens are typically poorly immunogenic and require effective adjuvants for antigen dose-sparing. Here, we evaluated chitosan microparticles (CSMs) and nanoparticles (CSNs) as polymeric nano-adjuvants for an H5N1 influenza vaccine, focusing on the roles of antigen dose and particle size. A purified hemagglutinin antigen was adsorbed onto chitosan particles at doses ranging from 0.15 to 5.0 µg. Both CSNs and CSMs showed consistently high loading efficiency (97-99%). BALB/c mice were immunized intramuscularly in a prime-boost schedule. Chitosan nanoparticles significantly enhanced IgG and hemagglutination inhibition (HI) titers at low antigen doses compared with aluminum hydroxide and antigen-only controls (p < 0.05). Immune responses reached saturation at a 1.5 µg dose of antigen for chitosan nanoparticles and 3.0 µg for chitosan microparticles. IgG subtype analysis suggested a balanced IgG1/IgG2a profile. Collectively, these findings support chitosan-based polymeric nanoparticles as promising adjuvants enabling dose-sparing H5N1 vaccination.
Keywords: H5N1 influenza vaccine; antigen dose-sparing; chitosan; hemagglutination inhibition; microparticles; nanoparticles; polymeric adjuvant.