Neutralizing antibodies against different SARS-CoV-2 variants of concern in convalescent and immunized individuals with different COVID-19 vaccines

• Grant number: 21/14197-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2022
• End date: April 01, 2025
• Field of knowledge: Biological Sciences - Immunology - Applied Immunology
• Principal Investigator: Edecio Cunha Neto
• Grantee: Isabela Pazotti Daher
• Host Institution: Instituto do Coração Professor Euryclides de Jesus Zerbini (INCOR). Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated scholarship(s): 22/14340-7 - Immunophenotyping T cells profile associated with COVID-19 vaccination and/or infection in people living with HIV (PLWH), BE.EP.DR

Abstract

Since the emergence of the "new coronavirus", that causes COVID-19 disease, health systems and economies around the world have been devastated by the spread of the virus, responsible for causing millions of deaths. Vaccines represent the most effective and safest method to control the COVID-19 pandemic. In order to accelerate the protection of individuals, some vaccines based on the Spike viral protein have been used as an antigen, such as vaccines based on mRNA (BNT162b2 - Pfizer), adenovirus (ChAdOx1 - AstraZeneca) and virus inactivated (Coronavac - Sinovac). Thus, it is expected that neutralizing antibodies induced by vaccination be able to protect individuals against the SARS-CoV-2. However, recent studies have shown that the emergence of SARS-CoV-2 variants with specific mutations in the Spike protein, can alter the binding with antibodies already produced and decrease the protection of vaccinated individuals. In this project, our hypothesis is that the reactivity profile of neutralizing antibodies in individuals infected with the Wuhan strain virus subsequently vaccinated will be distinct from the response of naïve individuals vaccinated with CoronaVac, AstraZeneca (ChAdOx1) or Pfizer (BNT12b2), against variants of concern. We aim to evaluate the humoral immune response and evolution of neutralizing antibody titers of individuals after COVID-19 infection and compare with the response obtained by naïve individuals after vaccination. To test our hypothesis, the specific antibody titers of convalescent and vaccinated individuals will be made by ELISA technique, and to determine levels of neutralization activity the samples will be tested against the WT variant (Wuhan), B.1.1.7 (United Kingdom), B.1.351 (South Africa), P.1 (Brazil) and B.1617.2 (Indiana) variants. Then, the data will be used to analyze if vaccines are able to induce protection against SARS-CoV-2 variants that are circulating in our country, and if resistance neutralization antibodies elicited by previous infection or vaccination is the same.