The viral spike protein in grey with the host receptor in red. The Phylex antigen is made of regions of the spike protein close to the receptor. Natural sugars carried by the protein are in blue.
Recent progress in computational analysis allows us to design antigens that are able to elicit specific classes of neutralizing antibodies, the primary defense against viral infection. These neutralizing antibodies will prevent virus entry into the host cell. The Phylex antigen is based on regions of the viral spike protein close to the host receptor. Our vaccine is both a universal and a complement vaccine. As a universal vaccine, it is designed to protect against the current and future variants of concern of the SARS-CoV-2 coronavirus, including the XBB.1.5, XBB.1.16 and EG.5 variants now prevalent worldwide, all with increased transmissibility and resistance to first and second generation vaccines. As a complement vaccine, it is designed to elicit a new class of neutralizing antibodies, different from the antibodies elicited by first and second generation vaccines and breakthrough infections. Therefore, it is expected to resolve the major issue of immune imprinting explained below. Finally, it is also designed to protect against viral dissemination and neuropathology associated with long COVID syndrome.
We have also developed a flexible mRNA nanoparticle platform for the rapid development of our vaccine candidate. A messenger RNA directly encodes for the self-assembling nanoparticle. This highly immunogenic nanoparticle displays 60 copies of our antigen and has a size, geometry and symmetry mimicking the virus. Recent results* show that our mRNA nanoparticle-based vaccine elicits a robust immune response with neutralizing antibodies and protective immunity against the delta variant.
*A mRNA vaccine encoding for a RBD 60-mer nanoparticle elicits neutralizing antibodies and protective immunity against the SARS-CoV-2 delta variant in transgenic K18-hACE2 mice
Frontiers in Immunology original research article published on July 6, 2022
*A mRNA vaccine encoding for a RBD 60-mer nanoparticle elicits neutralizing antibodies and protective immunity against the SARS-CoV-2 delta variant in transgenic K18-hACE2 mice
Frontiers in Immunology original research article published on July 6, 2022
A major issue with all current vaccines, including all vaccines due for the fall of 2023, is immune imprinting. Immune imprinting describes a narrow immune memory, limited to the wild type SARS-CoV-2 virus. Immune imprinting is caused by initial infection, as well as first and second generation vaccines and breakthrough infections. All vaccines to date contain epitopes in the spike protein common to the wild type SARS-CoV-2 virus that are preferentially recognized by the limited immune memory and elicit a narrow immune response. Our vaccine elicits a different class of neutralizing antibodies that complement and broaden the immune response.