Optimization and comparison of CD4-targeting lipid-polymer hybrid nanoparticles using different binding ligands

Area of Science:

• Biomaterials Science
• Nanotechnology
• Immunology

Background:

• Monoclonal antibodies and peptides are conjugated to nanocarriers (NCs) for targeted delivery.
• Targeting efficacy is influenced by the specificity, affinity, avidity of conjugates, and physicochemical properties of NCs.

Purpose of the Study:

• To compare the targeting efficacy of a CD4 binding peptide (BP4) and an anti-CD4 monoclonal antibody (CD4 mAb) and its fragments when conjugated to lipid-coated poly(lactic-co-glycolic) acid nanoparticles (LCNPs).
• To investigate the impact of NC surface charge on targeting specificity.

Main Methods:

• Lipid-coated poly(lactic-co-glycolic) acid nanoparticles (LCNPs) were prepared with varying surface charges.
• CD4 binding peptide (BP4), anti-CD4 monoclonal antibody (CD4 mAb), and its fragments were conjugated to negatively charged LCNPs (cbLCNPs).
• In vitro binding assays were performed using human T cell line 174xCEM and pigtail macaque peripheral blood mononuclear cells.

Main Results:

• Negatively charged cbLCNPs significantly reduced nonspecific binding and enhanced targeting specificity compared to neutral or positively charged LCNPs.
• CD4 mAb and its fragments conjugated to cbLCNPs demonstrated high in vitro binding to CD4+ T cells, while BP4 did not.
• CD4-cbLCNPs exhibited 10-fold higher binding specificity for CD4+ T cells over CD8+ T cells; fragment conjugates showed higher overall binding but lower specificity.

Conclusions:

• The ζ-potential of nanocarriers critically influences targeting efficacy.
• Anti-CD4 monoclonal antibody and its fragments are superior candidates for targeted delivery to CD4+ T cells compared to the BP4 peptide.
• Optimized nanocarrier formulation and targeting ligand selection are crucial for effective targeted therapy.