Memory B Cells and Memory T Cells Induced by SARS-CoV-2 Booster Vaccination or Infection Show Different Dynamics and Responsiveness to the Omicron Variant

• Published in: The Journal of immunology (1950) 2022-12, Vol.209 (11), p.2104-2113
• Main Authors: Mise-Omata, Setsuko, Ikeda, Mari, Takeshita, Masaru, Uwamino, Yoshifumi, Wakui, Masatoshi, Arai, Tomoko, Yoshifuji, Ayumi, Murano, Kensaku, Siomi, Haruhiko, Nakagawara, Kensuke, Ohyagi, Masaki, Ando, Makoto, Hasegawa, Naoki, Saya, Hideyuki, Murata, Mitsuru, Fukunaga, Koichi, Namkoong, Ho, Lu, Xiuyuan, Yamasaki, Sho, Yoshimura, Akihiko
• Format: Article
• Language: English
• Subjects: BNT162 Vaccine; COVID-19; Humans; Memory B Cells; Memory T Cells; SARS-CoV-2; Vaccination
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.2200525

Although the immunological memory produced by BNT162b2 vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been well studied and established, further information using different racial cohorts is necessary to understand the overall immunological response to vaccination. We evaluated memory B and T cell responses to the severe acute respiratory syndrome coronavirus 2 spike protein before and after the third booster using a Japanese cohort. Although the Ab titer against the spike receptor-binding domain (RBD) decreased significantly 8 mo after the second vaccination, the number of memory B cells continued to increase, whereas the number of memory T cells decreased slowly. Memory B and T cells from unvaccinated infected patients showed similar kinetics. After the third vaccination, the Ab titer increased to the level of the second vaccination, and memory B cells increased at significantly higher levels before the booster, whereas memory T cells recovered close to the second vaccination levels. In memory T cells, the frequency of CXCR5+CXCR3+CCR6- circulating follicular Th1 was positively correlated with RBD-specific Ab-secreting B cells. For the response to variant RBDs, although 60-80% of memory B cells could bind to the omicron RBD, their avidity was low, whereas memory T cells show an equal response to the omicron spike. Thus, the persistent presence of memory B and T cells will quickly upregulate Ab production and T cell responses after omicron strain infection, which prevents severe illness and death due to coronavirus disease 2019.