Nanocell COVID-19 vaccine triggers a novel immune response pathway producing high-affinity antibodies which neutralize all variants of concern

Most current anti-viral vaccines elicit a humoral and cellular immune response the pathway of phagocytic cell mediated viral antigen presentation to B and T cell surface receptors. However, this pathway results in reduced ability to neutralize S-protein Receptor Binding Domains (RBDs) from several V...

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Published inFrontiers in immunology Vol. 13; p. 1038562
Main Authors Gao, Steven Y, Amaro-Mugridge, Nancy B, Madrid-Weiss, Jocelyn, Petkovic, Nikolina, Vanegas, Natasha, Visvanathan, Kumar, Williams, Bryan R G, MacDiarmid, Jennifer A, Brahmbhatt, Himanshu
Format Journal Article
LanguageEnglish
Published Switzerland Frontiers Media S.A 27.01.2023
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Summary:Most current anti-viral vaccines elicit a humoral and cellular immune response the pathway of phagocytic cell mediated viral antigen presentation to B and T cell surface receptors. However, this pathway results in reduced ability to neutralize S-protein Receptor Binding Domains (RBDs) from several Variants of Concern (VOC) and the rapid waning of memory B cell response requiring vaccine reformulation to cover dominant VOC S-proteins and multiple boosters. Here we show for the first time in mice and humans, that a bacterially derived, non-living, nanocell (EDV; EnGeneIC Dream Vector) packaged with plasmid expressed SARS-CoV-2 S-protein and α-galactosyl ceramide adjuvant (EDV-COVID-αGC), stimulates an alternate pathway due to dendritic cells (DC) displaying both S-polypeptides and αGC thereby recruiting and activating iNKT cells with release of IFNγ. This triggers DC activation/maturation, activation of follicular helper T cells (T ), cognate help to B cells with secretion of a cytokine milieu promoting B cell maturation, somatic hypermutation in germinal centers to result in high affinity antibodies. Surrogate virus neutralization tests show 90-100% neutralization of ancestral and early VOC in mice and human trial volunteers. EDV-COVID-αGC as a third dose booster neutralized Omicron BA. 4/5. Serum and PBMC analyses reveal long lasting S-specific memory B and T cells. In contrast, control EDVs lacking αGC, did not engage the iNKT/DC pathway resulting in antibody responses unable to neutralize all VOCs and had a reduced B cell memory. The vaccine is lyophilized, stored and transported at room temperature with a shelf-life of over a year.
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Edited by: Luciana C. C. Leite, Butantan Institute, Brazil
Reviewed by: Fabio Fiorino, LUM University Giuseppe Degennaro, Italy; Nejat Duzgunes, University of the Pacific, United States
These authors have contributed equally to this work and share first authorship
This article was submitted to Vaccines and Molecular Therapeutics, a section of the journal Frontiers in Immunology
These authors contributed equally to senior authorship
ISSN:1664-3224
1664-3224
DOI:10.3389/fimmu.2022.1038562