Memory elicitation, T-cell response and antibody production: an independent study of an inactivated entire virus vaccine (Coronavac)

Abstract

Health professionals working to mitigate the COVID-19 pandemic are one of the main risk groups for the disease, being prioritized for vaccination. Considering this, the aim of this study was to analyze the immune response of these professionals immunized with CoronaVac in the first and second doses. Blood samples were collected after the first and second doses of the vaccine (CoronaVac) and used to investigate hematological and biochemical parameters, analysis of immunoglobulin production, cytokines, and gene expression profile, as well as the identification of subsets of immune cells. Post-first dose immunological phenotypic memory (CD27⁺) profiles (T CD4⁺, TCD8⁺ and CD19⁺) showed a significant increase, as did Monocyte APCs (CD80⁺HLA-DR⁺) in relation to the second dose. The cytokines IL-2, IL-6 and IFN-° showed increased values in relation to the other analyzed cytokines. The Th2/Th17 profile in the second dose was characterized by gene expression analysis. The production of IgM and IgG after vaccination showed statistically significant values in the comparison between doses. CoronaVac showed activation of APCs monocytes, memory response of T and B lymphocytes, with immunoglobulins production. This set of responses is characterized by the Th2/Th17 immunological profile.

Key words
CoronaVac; health professionals; immunological memory; immunoglobulin production; COVID-19; SARS-CoV-2