Combined PET and whole-tissue imaging of lymphatic-targeting vaccines in non-human primates.

Antigen accumulation in lymph nodes (LNs) is critical for vaccine efficacy, but understanding of vaccine biodistribution in humans or large animals remains limited. Using the rhesus macaque model, we employed a combination of positron emission tomography (PET) and fluorescence imaging to characterize the whole-animal to tissue-level biodistribution of a subunit vaccine comprised of an HIV envelope trimer protein nanoparticle (trimer-NP) and lipid-conjugated CpG adjuvant (amph-CpG). Following immunization in the thigh, PET imaging revealed vaccine uptake primarily in inguinal and iliac LNs, reaching distances up to 17 cm away from the injection site.

Targeting HIV Env immunogens to B cell follicles in nonhuman primates through immune complex or protein nanoparticle formulations.

Following immunization, high-affinity antibody responses develop within germinal centers (GCs), specialized sites within follicles of the lymph node (LN) where B cells proliferate and undergo somatic hypermutation. Antigen availability within GCs is important, as B cells must acquire and present antigen to follicular helper T cells to drive this process. However, recombinant protein immunogens such as soluble human immunodeficiency virus (HIV) envelope (Env) trimers do not efficiently accumulate in follicles following traditional immunization.

Calcium-triggered fusion of lipid membranes is enabled by amphiphilic nanoparticles.

Lipid membrane fusion is an essential process for a number of critical biological functions. The overall process is thermodynamically favorable but faces multiple kinetic barriers along the way. Inspired by nature's engineered proteins such as SNAP receptor [soluble N-ethylmale-imide-sensitive factor-attachment protein receptor (SNARE)] complexes or viral fusogenic proteins that actively promote the development of membrane proximity, nucleation of a stalk, and triggered expansion of the fusion pore, here we introduce a synthetic fusogen that can modulate membrane fusion and equivalently prime lipid membranes for calcium-triggered fusion.

Enhancing humoral immunity via sustained-release implantable microneedle patch vaccination.

Sustained exposure of lymphoid tissues to vaccine antigens promotes humoral immunity, but traditional bolus immunizations lead to rapid antigen clearance. We describe a technology to tailor vaccine kinetics in a needle-free platform translatable to human immunization. Solid pyramidal microneedle (MN) arrays were fabricated with silk fibroin protein tips encapsulating a stabilized HIV envelope trimer immunogen and adjuvant, supported on a dissolving polymer base.

Slow Delivery Immunization Enhances HIV Neutralizing Antibody and Germinal Center Responses via Modulation of Immunodominance.

Conventional immunization strategies will likely be insufficient for the development of a broadly neutralizing antibody (bnAb) vaccine for HIV or other difficult pathogens because of the immunological hurdles posed, including B cell immunodominance and germinal center (GC) quantity and quality. We found that two independent methods of slow delivery immunization of rhesus monkeys (RMs) resulted in more robust T follicular helper (T) cell responses and GC B cells with improved Env-binding, tracked by longitudinal fine needle aspirates. Improved GCs correlated with the development of >20-fold higher titers of autologous nAbs.

Synthesis of multivalent polymer-aptamer conjugates with enhanced inhibitory potency.

Purpose: We are interested in designing a modular strategy for creating potent multivalent ligands, which frequently can be used as effective inhibitors of undesired biomolecular interactions. For example, such inhibitors might prevent the self-assembly of bacterial toxins or the attachment of a virus to its host cell receptors.

Methods: We used a biocompatible polyamino acid polymer as a scaffold for grafting multiple copies of an oligonucleotide aptamer (OA).

Potential effect of ultrasound on carbohydrates.

The use of ultrasound has emerged as one of the most useful alternative energy sources for the synthesis of carbohydrate-derived biologically and pharmaceutically potential compounds. Spectacular advances have been made in the field of sonication-assisted organic reactions, which are known for producing superior yields, enhanced reactivity of the reactant, improved stereoselectivity, and shortened reaction times. Orthogonal protection-deprotection reactions and/or modification and manipulation of functional groups in carbohydrates are common synthetic steps in carbohydrate chemistry.

Recent advances in engineering polyvalent biological interactions.

Polyvalent interactions, where multiple ligands and receptors interact simultaneously, are ubiquitous in nature. Synthetic polyvalent molecules, therefore, have the ability to affect biological processes ranging from protein-ligand binding to cellular signaling. In this review, we discuss recent advances in polyvalent scaffold design and applications.

Design of monodisperse and well-defined polypeptide-based polyvalent inhibitors of anthrax toxin.

The design of polyvalent molecules, presenting multiple copies of a specific ligand, represents a promising strategy to inhibit pathogens and toxins. The ability to control independently the valency and the spacing between ligands would be valuable for elucidating structure-activity relationships and for designing potent polyvalent molecules. To that end, we designed monodisperse polypeptide-based polyvalent inhibitors of anthrax toxin in which multiple copies of an inhibitory toxin-binding peptide were separated by flexible peptide linkers.

Structure-based design of a heptavalent anthrax toxin inhibitor.

The design of polyvalent molecules, consisting of multiple copies of a biospecific ligand attached to a suitable scaffold, represents a promising approach to inhibit pathogens and oligomeric microbial toxins. Despite the increasing interest in structure-based drug design, few polyvalent inhibitors based on this approach have shown efficacy in vivo. Here we demonstrate the structure-based design of potent biospecific heptavalent inhibitors of anthrax lethal toxin.