Unmethylated CpG motif-containing genomic DNA fragments of bacillus calmette-guerin improves immune response towards a DNA vaccine for COVID-19

Vaccine. 2021 Oct 1;39(41):6050-6056. doi: 10.1016/j.vaccine.2021.08.103. Epub 2021 Sep 3.

Abstract

The development of an effective vaccine to control the global coronavirus disease-2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus- 2 (SARS-CoV-2) is of utmost importance. In this study, a synthetic DNA-based vaccine candidate, known as pSV10-SARS-CoV-2, expressing the SARS-CoV-2 spike protein was designed and tested in 39 BALB/c mice with BC01, an adjuvant derived from unmethylated CpG motif-containing DNA fragments from the Bacillus Calmette-Guerin genome. Mice vaccinated with pSV10-SARS-CoV-2 with BC01 produced early neutralizing antibodies and developed stronger humoral and cellular immune responses compared to mice that received the DNA vaccine only. Moreover, sera from mice vaccinated with pSV10-SARS-CoV-2 with BC01 can neutralize certain variants, including 614G, 614G + 472 V, 452R, 483A, 501Y.V2, and B.1.1.7. The results of this study demonstrate that the addition of BC01 to a DNA-vaccine for COVID-19 could elicit more effective neutralizing antibody titers for disease prevention.

Keywords: BC01 adjuvant; COVID-19; DNA vaccine; SARS-COV-2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • BCG Vaccine
  • COVID-19 Vaccines
  • COVID-19*
  • DNA
  • Genomics
  • Humans
  • Immunity, Cellular
  • Mice
  • Mice, Inbred BALB C
  • SARS-CoV-2
  • Spike Glycoprotein, Coronavirus / genetics
  • Vaccines, DNA*

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • BCG Vaccine
  • COVID-19 Vaccines
  • Spike Glycoprotein, Coronavirus
  • Vaccines, DNA
  • spike protein, SARS-CoV-2
  • DNA