INO-4800 DNA Vaccine Induces Neutralizing Antibodies and T cell Activity Against Global SARS-CoV-2 Variants
Open Forum Infectious Diseases
; 8(SUPPL 1):S390-S391, 2021.
Article
in English
| EMBASE | ID: covidwho-1746420
ABSTRACT
Background. Global surveillance has identified emerging SARS-CoV-2 variants of concern (VOC) associated with increased transmissibility, disease severity, and resistance to neutralization by current vaccines under emergency use authorization (EUA). Here we assessed cross-immune responses of INO-4800 vaccinated subjects against SARS-CoV-2 VOCs. Methods. We used a SARS-CoV-2 IgG ELISA and a pseudo neutralization assay to assess humoral responses, and an IFNγ ELISpot to measure cellular responses against SARS-CoV-2 VOC in subjects immunized with the DNA vaccine, INO-4800. Results. IgG binding titers were not impacted between wild-type (WT) and B.1.1.7 or B.1.351 variants. An average 1.9-fold reduction was observed for the P.1 variant in subjects tested at week 8 after receiving two doses of INO-4800 (Figure 1a). We performed a SARS-CoV-2 pseudovirus neutralization assay using sera collected from 13 subjects two weeks after administration of a third dose of either 0.5 mg, 1 mg, or 2 mg of INO-4800. Neutralization was detected against WT and the emerging variants in all samples tested. The mean ID50 titers for the WT, B.1.1.7, B.1.351 and P.1. were 643 (range 70-729), 295 (range 46-886), 105 (range 25-309), and 664 (range 25-2087), respectively. Compared to WT, there was a 2.1 and 6.9-fold reduction for B.1.1.7 and B.1.351, respectively, while there was no difference between WT and the P.1 variant (Figure 1b). Next, we compared cellular immune responses to WT and SARS-CoV-2 Spike variants elicited by INO-4800 vaccination. We observed similar cellular responses to WT (median = 82.2 IQR = 58.9-205.3), B.1.1.7 (79.4, IQR = 38.9- 179.7), B.1.351 (80, IQR = 40.0-208.6) and P.1 (78.3, IQR = 53.1-177.8) Spike peptides (Figure 2). Conclusion. INO-4800 vaccination induced neutralizing antibodies against all variants tested, with reduced levels detected against B.1.351. IFNγ T cell responses were fully maintained against all variants tested.
DNA vaccine; endogenous compound; gamma interferon; immunoglobulin G; neutralizing antibody; reluscovtogene ralaplasmid; adult; cell activity; cellular immunity; clinical article; conference abstract; controlled study; drug therapy; enzyme linked immunospot assay; female; human; human experiment; humoral immunity; ID50; immune response; male; nonhuman; SARS coronavirus 2 immunology test kit; SARS-CoV-2 variant 501Y.V2; Severe acute respiratory syndrome coronavirus 2; spike; T lymphocyte; vaccination; wild type
Full text:
Available
Collection:
Databases of international organizations
Database:
EMBASE
Topics:
Vaccines
/
Variants
Language:
English
Journal:
Open Forum Infectious Diseases
Year:
2021
Document Type:
Article
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