Immune Assessment of BNT162b2 m-RNA-Spike Based Vaccine Response in Adults

• Main Authors: David San Segundo, Alejandra Comins-Boo, Juan Irure-Ventura, Mónica Renuncio-García, Adriel Roa-Bautista, Elena González-López, David Merino-Fernández, Patricia Lamadrid-Perojo, Marta Alonso-Peña, Javier Gonzalo Ocejo-Vinyals, Maria Gutiérrez-Larrañaga, Sandra Guiral-Foz, Marcos López-Hoyos
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Biomedicines
• Subjects: SARS-CoV-2; vaccines; T-specific response; B-specific response; T follicular helper cells
• Online Access: https://www.mdpi.com/2227-9059/9/8/868

Vaccine efficacy is based on clinical data. Currently, the assessment of immune response after SARS-CoV-2 vaccination is scarce. A total of 52 healthcare workers were immunized with the same lot of BNT162b2 vaccine. The immunological response against the vaccine was tested using a T-specific assay based on the expression of CD25 and CD134 after stimulation with anti-N, -S, and -M specific peptides of SARS-CoV-2. Moreover, IgG anti-S2 and -RBD antibodies were detected using ELISA. Furthermore, the cell subsets involved in the response to the vaccine were measured in peripheral blood by flow cytometry. Humoral-specific responses against the vaccine were detected in 94% and 100% after the first and second doses, respectively. Therefore, anti-S T-specific responses were observed in 57% and 90% of the subjects after the first and second doses of the vaccine, respectively. Thirty days after the second dose, significant increases in T helper 1 memory cells (<i>p</i> < 0.001), peripheral memory T follicular helper (pT_FH) cells (<i>p</i> < 0.032), and switched memory (<i>p</i> = 0.005) were observed. This study describes the specific humoral and cellular immune responses after vaccination with the new mRNA-based BNT162b2 vaccine. A mobilization of T_FH into the circulation occurs, reflecting a specific activation of the immune system.