Coronavirus cell in microscopic view. Virus Vaccine Development

SNAP Vaccine Platform

The SNAP (Spontaneous Nanoliposome Antigen Particleization) platform technology is a unique liposome-based system that functions as a potent vaccine adjuvant designed to address functional and practical limitations facing vaccine development.

Recombinant proteins and peptides represent a safe and simple method of vaccine production with the added benefits of defined antigenicity, rapid manufacturing and scale up. However, recombinant proteins often fail to produce a robust immune response, leading to a lack of protection against the disease of interest.  In order to generate a viable immune response, antigens are often coupled to immunogenic carriers,  nanoparticles, or engineered into virus-like particles, a labor-intensive process with significant detriments for vaccine development and manufacturing. The SNAP platform seeks to address these limitations by providing a novel nanoparticle platform that has the functional simplicity of conventional vaccine adjuvants.


The SNAP approach involves simple incubation of His-tagged antigens with SNAP-liposomes (Figure 1A), leading to the insertion of the His-tagged antigen into the bilayer and coordination with cobalt chelated in the porphyrin lipid, forming a His-tag membrane anchor (Figure 1B).

SNAP liposomes before (left) and after incubation (right) resulting in binding of antigen

Influenza virus HA admixed with SNAP liposomes

Instantly Harness the Power of Particle-Based Vaccines

• SNAP liposomes contain Cobalt porphyrin phospholipid (CoPoP) and the lipid adjuvants synthetic MPLA and optionally QS-21

• CoPoP enables rapid and biostable display of antigens on liposomes with simple mixing.

•SNAP focuses the immune response on antigen of interest with protein-free scaffold technology

•Requires a conventional his-tagged antigen (4-10X) for usage

Potent, sustained
immune responses

•SNAP enhances antibody responses for his-tagged protein and peptide antigens
• Antibody half-life in mice demonstrated to approach one year in multiple studies
• Strong cellular responses also observed

 Straightforward Multiplexing

• SNAP is ideal for multivalent immunization.
• SNAP demonstrated for 10-plex protein antigens
• A single peptide in a SNAP vaccine remained even when multiplexed with 59 other peptides.

Mechanism of potency

• SNAP provides improved depot effect and better uptake of antigens by immune cells in the lymph node
• Co-delivery of adjuvants along with antigens to same immune cells further enhance immune response

Clinical-stage, versatile adjuvant system

• Part of EuCorVac-19, tested in a 280 person ph1/2 trial.
• CoPoP produced under GMP at 2.5M dose scale. Other components are available under GMP.
• Compatible and with pre-mixing, two-vial mixing, and lyophilization

Seeking collaboration to assess SNAP technology

•POP BIO holds exclusive license to the SNAP patent portfolio
•Excellent results obtained independently by > 5 separate collaborators
•SNAP liposomes, controls, and simple assays for characterizing particles ready to ship out

Selected peer reviewed publications (of > 15)

Nature Chemistry, 2015: Functionalization of cobalt porphyrin-phospholipid bilayers with his-tagged ligands and antigens
Nature Nanotechnology, 2018: A malaria vaccine adjuvant based on recombinant antigen binding to liposomes
Advanced Materials, 2020. SARS-CoV-2 RBD Neutralizing Antibody Induction is Enhanced by Particulate Vaccination
Vaccine, 2020: Immunogenicity of the Lyme disease antigen OspA, particleized by cobalt porphyrin-phospholipid liposomes
JITC, 2021: Immunization with short peptide particles reveals a functional CD8+ T-cell neoepitope in a murine renal carcinoma model
PNAS, 2021: A liposome-displayed hemagglutinin vaccine platform protects mice and ferrets from heterologous influenza virus challenge
Science Adv, 2021: Lyophilized, thermostable Spike or RBD immunogenic liposomes induce protective immunity against SARS-CoV-2 in mice

POP BIO seeks collaborators around the SNAP platform

POP BIO holds exclusive global license to the SNAP patent portfolio and has excellent results obtained, independently, with numerous active collaborations with a variety of industry partners.

SNAP Liposomes, controls, and simple assays for characterization are ready for immediate transfer and shipment.