This article is a Preprint
Preprints are preliminary research reports that have not been certified by peer review. They should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Preprints posted online allow authors to receive rapid feedback and the entire scientific community can appraise the work for themselves and respond appropriately. Those comments are posted alongside the preprints for anyone to read them and serve as a post publication assessment.
SARS-CoV-2 S1 Subunit Booster Vaccination Elicits Robust Humoral Immune Responses in Aged Mice
Preprint
in English
| bioRxiv
| ID: ppbiorxiv-513090
ABSTRACT
Currently approved COVID-19 vaccines prevent symptomatic infection, hospitalization, and death of the disease. However, the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants raises concerns of reduced vaccine effectiveness and increased risk of infection. Repeated homologous booster in elderly individuals and immunocompromised patients is considered to solve severe form of disease caused by new SARS-CoV-2 variants but cannot protect completely against breakthrough infection. In our previous study we assessed the immunogenicity of an adenovirus-based vaccine expressing SARS-CoV-2-S1 (Ad5.S1) in mice, resulting in that a single immunization with Ad5.S1, via subcutaneously injection or intranasal delivery, induced robust humoral and cellular immune responses [1]. As a follow up study, here we showed that vaccinated mice had high titers of anti-S1 antibodies at one year after vaccination compared to PBS immunized mice. Furthermore, one booster dose of non-adjuvanted recombinant S1Beta (rS1Beta) subunit vaccine was effective in stimulating strong long-lived S1-specific immune responses and inducing significantly high neutralizing antibodies against the Wuhan, Beta, and Delta strain with 3.6- to 19.5-fold change increases. Importantly, the booster dose elicits cross-reactive antibody responses resulting in ACE2 binding inhibition against spike of SARS-CoV-2 variants (Wuhan, Alpha, Beta, Gamma, Delta, Zeta, Kappa, New York, India) as early as two-week post-boost injection, persisting over 28 weeks after a booster vaccination. Interestingly, levels of neutralizing antibodies were correlated with not only level of S1-binding IgG but also level of ACE2 inhibition in the before- and after-booster serum samples. Our findings show that S1 recombinant protein subunit vaccine candidate as a booster has potential to offer cross-neutralization against broad variants, and has important implications for vaccine control of new emerging breakthrough SARS-CoV-2 variants in elderly individuals primed with adenovirus-based vaccine like AZD1222 and Ad26.COV2.S.
cc_by_nc_nd
Full text:
Available
Collection:
Preprints
Database:
bioRxiv
Type of study:
Cohort_studies
/
Experimental_studies
/
Prognostic study
/
Rct
Language:
English
Year:
2022
Document type:
Preprint