Evaluation of the humoral immune response to different variants of SARS-CoV-2 in Brazilians vaccinated with monovalent vaccines.

• Grant number: 23/14378-7
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: February 13, 2024
• End date: February 12, 2025
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Principal Investigator: Alessandro dos Santos Farias
• Grantee: Natália Brunetti Silva
• Supervisor: Richard James Stanton
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Cardiff University, Wales
• Associated to the scholarship: 19/13552-8 - Evaluation of the humoral and cellular protective potentials of vaccines against SARS-CoV-2 different lineages, BP.DD

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was discovered in 2019 in Wuhan, China, and caused almost 7 million deaths to date. Brazil is the second country with the highest number of deaths. The lack of drugs with scientifically proven efficacy to prevent or treat SARS-CoV-2 infection and the need to contain COVID-19 has made it necessary to urgently develop new vaccine formulations. The concentration of global financial resources, as well as the technological and scientific advances in the area, have made it possible to develop 382 vaccines in a reduced period. Previous studies combating zoonotic epidemics enabled the identification of the antigenic target Spike, specifically its receptor-binding domain (RBD). It is a highly variable region that can undergo mutations due to selective pressure mediated by antibodies, which can affect infectivity, viral load, and virus transmissibility. The emergence of SARS-CoV-2 variants with mutations in the RBD domain is a concern for the scientific community regarding the control of the pandemic, as it may compromise the humoral immune response via antibody neutralization escape. Despite having proven effective in combating the disease and reducing the number of severe cases, little is known about the humoral and cellular protective potential of these vaccines applied in Brazil in relation to the virus and its variant lineages. In a study published by our group in collaboration with other researchers, we observed that the variant of concern P.1 can escape the neutralization of antibodies from convalescent patients and individuals previously immunized with the CoronaVac and that this neutralization capacity is six times smaller when compared to the original lineage of SARS-CoV-2. The antibody-dependent cellular cytotoxicity response (ADCC) that can also significantly impact the course of virus infection has not been extensively studied. Given the above, it is our objective with this proposal to evaluate the Fc receptor-dependent antibody activities generated by vaccines against different lineages of SARS-CoV-2 circulating in Brazil and other aspects of the humoral and cellular immune response, ensuring the effectiveness of immunization programs.