Modified dipeptide based nanospheres as a potent adjuvating delivery system for recombinant vaccines

Area of Science:

• Biotechnology
• Nanotechnology
• Vaccinology

Background:

• Recombinant protein vaccines require adjuvants to enhance immunogenicity due to low antigenicity.
• Nanotechnology offers a platform for developing non-toxic, biodegradable, and biocompatible vaccine adjuvants.
• There is a need for novel delivery systems with inherent adjuvant properties.

Purpose of the Study:

• To synthesize and characterize a modified dipeptide, Arg-α, β-dehydrophenyalanine (RΔF), as a nanoparticle-based vaccine adjuvant.
• To evaluate the biocompatibility and immunogenicity of RΔF nanoparticles carrying a recombinant Plasmodium falciparum antigen (Fu24H).
• To compare the efficacy of the RΔF-Fu24H nanoformulation with an approved adjuvant, Alhydrogel®.

Main Methods:

• Synthesis and characterization of RΔF dipeptide using RP-HPLC and mass spectrometry.
• Self-assembly of RΔF into nanoparticles (NPs) and complexation with histidine-tagged MSPFu24 (Fu24H).
• Evaluation of nanoparticle morphology via TEM, in vitro and in vivo biocompatibility assays, and assessment of humoral and cellular immune responses in mice.

Main Results:

• RΔF self-assembled into spherical nanoparticles that efficiently condensed the Fu24H antigen.
• RΔF NPs and the RΔF-Fu24H complex demonstrated excellent in vitro and in vivo biocompatibility.
• The RΔF-Fu24H nanoformulation induced high titers of anti-Fu24H antibodies and a mixed Th1/Th2 immune response, comparable to Alhydrogel®.
• Immune sera inhibited P. falciparum erythrocyte invasion in vitro.

Conclusions:

• The RΔF dipeptide-based nanoparticle formulation is a highly biocompatible and effective antigen delivery platform.
• This novel nanoformulation shows significant potential as a vaccine adjuvant for eliciting robust immune responses.
• The study suggests clinical applicability for RΔF nanoparticles in developing next-generation vaccines.