Antibodies and Vaccines Target RBD of SARS-CoV-2

Abstract

The novel human coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which gives rise to the coronavirus disease 2019 (COVID-19), has caused a serious threat to global public health. On March 11, 2020, the WHO had officially announced COVID-19 as a pandemic. Therefore, it is vital to find effective and safe neutralizing antibodies and vaccines for COVID-19. The critical neutralizing domain (CND) that is contained in the receptor-binding domain (RBD) of the spike protein (S protein) could lead to a highly potent neutralizing antibody response as well as the cross-protection of other strains of SARS. By using RBD as an antigen, many neutralizing antibodies are isolated that are essential to the therapeutics of COVID-19. Furthermore, a subunit vaccine, which is based on the RBD, is expected to be safer than others, thus the RBD in the S protein is a more important target for vaccine development. In this review, we focus on neutralizing antibodies that are targeting RBD as well as the vaccine based on RBD under current development.

Keywords: COVID-19; RBD; SARS-CoV-2; antibodies; vaccines.

FIGURE 1

Schematic diagram of the SARS-CoV-2 coronavirus particle. Four structure proteins contain the envelope protein (E), nucleocapsid protein (N), spike protein (S), and membrane protein (M). SARS-CoV-2 virus enters the cell through the S protein on the surface of SARS-CoV-2 by means of binding with its receptor ACE2. The S protein is mainly divided into S1, which contains RBD, and S2 subunits. Created by BioRender.com. ACE2, angiotensin-converting enzyme 2; SARS-CoV-2, severe acute respiratory syndrome coronavirus-2; RBD, receptor-binding domain.

FIGURE 2

The immune response caused through a vaccine. The mRNA of the RBD of the S protein of SARS-CoV-2 can translate on the ribosome of the host, and then the foreign protein of RBD reduces to a polypeptide to stimulate the immune system and is caught by the antigen-presenting cells (APCs) which can process the vaccine antigen and present it to the CD4 T⁺ cells and CD8 T⁺ cells. It acquires the ability to treat SARS-CoV-2 by activating B cells to produce antibodies and T cells to attack the infected cells. Created by BioRender.com. SARS-CoV-2, severe acute respiratory syndrome coronavirus-2; RBD, receptor-binding domain.