Perfil dos linfócitos de memória em individuos vacinados para COVID-19

Abstract

COVID-19 is a disease that began in the city of Wuhan, China, and quickly spread across the world, leading the World Health Organization to declare a pandemic in March 2020. Due to the high number of deaths caused by the disease, scientific advancements in the search for prevention and treatment methods against SARS CoV-2 led to the development of different vaccine platforms. Research evaluating the efficacy of vaccines after immunization showed varying results regarding the immune response induced by vaccination, due to the different vaccines available. Therefore, understanding more about the cellular immune response under different protocols is important to better comprehend the vaccine-induced response. Our objective in this study was to evaluate the profile of memory T and B lymphocytes and follicular T cells in individuals vaccinated against COVID-19. We collected peripheral blood samples from 12 vaccinated individuals, separated mononuclear cells, cultured them with the SARS-CoV-2 RBD antigen, and analyzed the memory T and B lymphocytes and follicular T cells using flow cytometry. Additionally, levels of IFN-γ and IL-10 in the culture supernatants were measured by ELISA. As a result, we found higher frequencies of EMRA and EM T cells in vaccinated participants and across subgroups (homologous, heterologous, 3 and 4 doses). We observed increased expression of IFN-γ and TGF-β by EM T cells, as well as higher levels of IL-10 and IFN-γ in the supernatants of stimulated cultures from vaccinated participants. Our results suggest that, regardless of the vaccination protocol, the immune response is similar and effective.