Effects of the induction of humoral and cellular immunity by third vaccination for SARS-CoV-2.

Publication date: Apr 01, 2024

To control the spread of severe disease caused by mutant strains of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), it is necessary to determine whether continued vaccination enhances humoral and cellular immunity. In this study, we examined the changes in humoral and cellular immunity to SARS-CoV-2 after administration of the third vaccination in healthy Japanese adults who had received the second dose of messenger ribonucleic acid (mRNA)-1273 vaccine and the third vaccination (BNT162b2 or mRNA-1273). We measured anti-spike antibodies in immunoglobulin G (IgG) and anti-nucleocapsid IgG titers in the serum of the vaccinated subjects. To evaluate cellular immunity, the peripheral blood mononuclear cells of inoculated individuals were cultured with spiked proteins, including those of the SARS-CoV-2 conventional strain and Omicron strain, and then subjected to enzyme-linked immunospot (ELISPOT). The results revealed that the anti-SARS-CoV-2 spike protein antibody titer increased after the third vaccination and was maintained; however, a decrease was observed at 6 months after vaccination. SARS-CoV-2 antigen-specific T helper (Th)1 and Th2 cell responses were also induced after the third vaccination and were maintained for 6 months after vaccination. Furthermore, induction of cellular immunity against Omicron strains by the omicron non-compliant vaccines, BNT162b2 or mRNA-1273, was observed. These findings demonstrate the effectiveness of vaccination against unknown mutant strains that may occur in the future and provide important insights into vaccination strategies.

Concepts Keywords
Bnt162b2 Cellular immunity
Coronavirus Humoral immunity
Cultured Omicron
Japanese SARS-CoV-2
Mutant vaccination


Type Source Name
disease VO vaccination
disease VO Severe acute respiratory syndrome coronavirus 2
disease VO dose
disease VO vaccine
disease VO vaccinated
disease IDO blood
disease VO antibody titer
disease IDO cell
disease VO effectiveness

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