Development characterizations and evaluation of Poly(-ε-caprolactone)-based microspheres for hepatitis B surface...

Area of Science:

• Biomaterials Science
• Vaccinology
• Immunology

Background:

• Current vaccines often require multiple administrations, limiting patient compliance and vaccine efficacy.
• Developing sustained-release vaccine formulations is crucial for improving immunization strategies.

Purpose of the Study:

• To create long-acting poly(-ε-caprolactone) (PCL) microspheres for delivering recombinant hepatitis B surface antigen (rHBsAg).
• To evaluate the immunogenicity and antigen integrity of rHBsAg delivered via PCL microspheres after intramuscular administration.

Main Methods:

• PCL microspheres encapsulating rHBsAg were prepared and characterized for physical properties and antigen integrity.
• Differential Scanning Calorimetry (DSC) and Circular Dichroism (CD) spectroscopy were used to assess encapsulation and antigen conformation.
• SDS-PAGE confirmed antigen integrity.
• Immunogenicity was assessed by measuring cellular (IFN-γ, IL-2) and humoral (IgG) responses in BALB/c mice.

Main Results:

• PCL microspheres demonstrated efficient encapsulation of rHBsAg.
• Antigen integrity and secondary structure were maintained after encapsulation and release.
• A single intramuscular immunization with HBsAg PCL microspheres significantly upregulated cellular and IgG responses.
• The immune response was superior to that induced by conventional alum adjuvant.

Conclusions:

• PCL microspheres provide an effective long-acting delivery system for hepatitis B vaccines.
• These microspheres enhance immune responses, offering a promising alternative to conventional vaccine formulations.
• This technology holds potential for improving hepatitis B prevention strategies through single-dose administration.