Enhanced Systemic and Mucosal Immune Responses to <i>Haemophilus parasuis</i> by Intranasal Administration of Lactic-Co-Glycolic Acid Microspheres

Abstract

Swine Glasser’s disease, instigated by Haemophilus parasuis (H. parasuis), is a significant bacterial infection that causes substantial economic losses in pig farming operations. The role of mucosal immunity is pivotal in defending against H. parasuis. This study focused on the construction of PLGA microspheres that encapsulate the outer membrane protein OMP16 from H. parasuis (PLGA-OMP16) and evaluated their immunological effectiveness in a mouse model. After being intranasally immunized twice, the PLGA-OMP16 microspheres effectively induced IgAs in saliva and nasal and lung fluids. The PLGA-OMP16 microspheres also significantly increased the number of anti H. parasuis IgGs in serum. Furthermore, the PLGA-OMP16 microspheres triggered elevated levels of IL-2, IL-4, and IFN-γ. The mice vaccinated with PLGA-OMP16 showed a significant reduction in H. parasuis burden in the spleen and lungs following bacterial challenge. These results indicate that intranasal immunization using PLGA microspheres is a promising adjuvant delivery system for vaccines targeting H. parasuis.

Keywords

• <i>Haemophilus parasuis</i>
• PLGA
• vaccine
• adjuvant
• mucosal immune
• intranasal