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Heterologous SaRNA Prime, DNA Dual-Antigen Boost SARS-CoV-2 Vaccination Elicits Robust Cellular Immunogenicity and Cross-Variant Neutralizing Antibodies

Abstract

We assessed if immune responses are enhanced in CD-1 mice by heterologous vaccination with two different nucleic acid-based COVID-19 vaccines: a next-generation human adenovirus serotype 5 (hAd5)-vectored dual-antigen spike (S) and nucleocapsid (N) vaccine (AdS+N) and a self-amplifying and -adjuvanted S RNA vaccine (AAHI-SC2) delivered by a nanostructured lipid carrier. The AdS+N vaccine encodes S modified with a fusion motif to increase cell-surface expression and an N antigen modified with an Enhanced T-cell Stimulation Domain (N-ETSD) to direct N to the endosomal/lysosomal compartment and increase MHC class I and II stimulation potential. The S sequence in the AAHI-SC2 vaccine comprises the D614G mutation, two prolines to stabilize S in the prefusion conformation, and 3 glutamines in the furin cleavage region to confer protease resistance. CD-1 mice received vaccination by homologous and heterologous prime > boost combinations. Humoral responses to S were the highest with any regimen that included the AAHI-SC2 vaccine, and IgG bound to wild type and Delta (B.1.617.2) variant S1 at similar levels. An AAHI-SC2 prime followed by an AdS+N boost particularly enhanced CD4+ and CD8+ T-cell responses to both wild type and Delta S peptides relative to all other vaccine regimens. Sera from mice receiving AAHI-SC2 homologous or heterologous vaccination were found to be highly neutralizing for all pseudovirus strains tested: Wuhan, Beta, Delta, and Omicron strains. The findings here, taken in consideration with the availability of both vaccines in thermostable formulations, support the testing of heterologous vaccination by an AAHI-SC2 > AdS+N regimen in animal models of SARS-CoV-2 infection to assess its potential to provide increased protection against emerging SARS-CoV-2 variants particularly in regions of the world where the need for cold-chain storage has limited the distribution of other vaccines.

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References
1.
Hyseni I, Molesti E, Benincasa L, Piu P, Casa E, Temperton N . Characterisation of SARS-CoV-2 Lentiviral Pseudotypes and Correlation between Pseudotype-Based Neutralisation Assays and Live Virus-Based Micro Neutralisation Assays. Viruses. 2020; 12(9). PMC: 7551040. DOI: 10.3390/v12091011. View

2.
Amalfitano A, Hauser M, Hu H, Serra D, Begy C, Chamberlain J . Production and characterization of improved adenovirus vectors with the E1, E2b, and E3 genes deleted. J Virol. 1998; 72(2):926-33. PMC: 124562. DOI: 10.1128/JVI.72.2.926-933.1998. View

3.
Kardani K, Bolhassani A, Shahbazi S . Prime-boost vaccine strategy against viral infections: Mechanisms and benefits. Vaccine. 2015; 34(4):413-423. DOI: 10.1016/j.vaccine.2015.11.062. View

4.
Tan A, Linster M, Tan C, Bert N, Chia W, Kunasegaran K . Early induction of functional SARS-CoV-2-specific T cells associates with rapid viral clearance and mild disease in COVID-19 patients. Cell Rep. 2021; 34(6):108728. PMC: 7826084. DOI: 10.1016/j.celrep.2021.108728. View

5.
Rice A, Verma M, Shin A, Zakin L, Sieling P, Tanaka S . Intranasal plus subcutaneous prime vaccination with a dual antigen COVID-19 vaccine elicits T-cell and antibody responses in mice. Sci Rep. 2021; 11(1):14917. PMC: 8295250. DOI: 10.1038/s41598-021-94364-5. View